There's a couple of things that throw a wrench into your arguments.
First, there are already PC exclusives that sell for less on Steam despite having no console equivalents and I'm not just talking about F2Ps and small indie titles. The Total War series for instance has never been ported to the consoles. ARMA, never ported to the consoles. Civilization, never ported. These games are released on Steam for $50-60 and then go down in price pretty quickly. The reason prices are lowered is because they figure that everyone who will buy a game at $60 will buy it before and around the official release date. Then they sell it at $40 a month or two later to capture those people and then later at $20 and so on.
Second. Steam AND the developers/publishers make money regardless of whether a game is sold at $60 or $5. They just make less money if it's sold at $5. If Gamestop sells a brand new game for $5, someone (possibly everyone) is losing money in that proposition.
Agreed, Steam offers more and PC gaming is inherently different enough from console that people should stop saying that XBone's (old) DRM was "exactly like Steam." There are things that happen with PC games that simply don't occur on consoles. A game like ARMA2 for instance jumped onto the Steam top seller list years after it was released because of the Day Z mod. There's no equivalent of that happening on consoles.
That's not how it works on Steam though. Look at their top sellers right now. Four of the top ten games are $50 or more. An additional two are over $40. Valve doesn't release numbers but I would imagine the amount of sales generated is significant since there are 20 million+ users on Steam. It's not as if Skyrim was released, Steam users ignored it and then they sold gangbusters during the Christmas sale. It was more like it was released, sold gangbusters. Sold even more gangbusters during the Christmas sale and is selling even more gangbuster now that they have the legendary edition up even though it's $60.
Nobody said this. Digital Distribution allows companies to make profit at all price levels and relatively quickly.
I agree with some of what you've said i.e. that there are premium sales on the PC. However, the wrenches you bring up don't fully refute the fact that piracy and console revenues drive the pricing model on Steam. Simply restating the mechanics of Steam sales and saying "gangbusters" and exclaiming how much "value" is inherent within the PC platform doesn't account for the reality that the majority of PC developers with big budgets could never make it back exclusively on PC/Steam at the current levels of pricing and generous price reduction. I accept there are exceptions to this rule - but if you'd like - I'd be happy to have a PM conversation about this with some financial modeling.
I also think you aren't fully understanding how retail works. The way you describe Steam sales is similar to how retail works - except prices are slightly higher to account for the physical package and shipping and retail margin (but comes with resale ability for the user). The flipside of the higher price for pubs is that they get the benefit of fronted money from wholesalers nor do you have the placement marketing/discovery aspect that is important. IMHO that is pretty important, particularly for large pubs.
Retail (primarily console) games come out and drop to 40 or 20 in a very short period (minus Nintendo which generally refuses to reduce the price of its software and has a track record of evergreen hits). I got MGS: Rising for 20 bucks two months after it came out for the X360. Relative to Steam - the only difference is the economics might be slightly different, but there are pros and cons to that which you are just glossing over.
My estimation is half the AAA multi plat games would be sent to die as PC exclusives at the budgets they have if Steam functioned the way it did. It's not just me saying this, there is a reason why formerly PC-exclusive developers got into the console game, and build their games with minimum spec around them. Even Crytek said this over two years ago saying that big budget PC games just aren't happening on the same level they once were because of the price deflation and expectations of PC gamers in terms of follow-up support - not to mention rampant piracy. In the 90s and early 00s, these same devs could make enough money on the PC alone to justify "big" budget games.
I think games like Total War are great, but its budget hardly comes close to AAA multi plat games. What did Total War sell? Less than 1.2 million for the absolute best selling SKU after lots of sales? You realize that the average cost of a AAA game is $30-40M right? For a game to generate profits you need to be at least 50% above its total cost of production provided a three year development horizon and cost of capital of 12% (which is frankly generous, my experience in the industry is that 20% is more appropriate for cost of capital which means they need to get 2x cost of production at a minimum in terms of net revenue).
Civilization has a long history on the PC and I think they had enough of a PC fanbase to make their money back. But the game itself didn't have a gigantic budget, and two games are a far cry from the exclusives the PC used to see. In a console-less and DD-only world, I don't believe people conditioned on $5 games on Steam are going to keep all these publishers afloat. It's going to require the industry to fundamentally restructure and many of these games become impossible. While I'd personally be in favor of that (you can read my earlier topics on this issue) - there would be a huge bloodbath.
BTW just so you know - I'm not a console fanboy, I'm primarily a PC gamer - and have been since the 80s - I understand and appreciate the implications of Steam - but it's just wrong to say that we haven't benefitted from the fact that consoles exist and generate premium revenue in the past eight years. I accept that the PC is hardly the primordial platform it once was, but that's fine because it means we get the best pricing and promotions being the tail end of the revenue distribution curve. That said, the minute Steam sales represent 30-40% of units - we are screwed - because publishers are going to finely tune and manage sales to ensure they are extracting higher revenues.
P.S.
The PS3 and X360 have a combined userbase of 160 million, and games like Tomb Raider sell 3.4 million globally fronted by wholesalers. Do you really think Steam's 20 million users are going to be so "gangbusters" in terms of premium sales that they can make it up - especially when the revenue generated per user is going to be far less on average?
But majority of pc games aren't ports from consoles. This market exist on it's own. And sells well in many price points. The advantage of pc as a platform is flexibility. You can get DD, you can make huge price cuts for promotions or you can release games cheaply through local distributors (fees paid to console manufacturers make this impossible), cheap enough to have a lot of people pick the legal copy up instead of pirating.
This is market that lives from PC centric devs. Those console ports aren't exactly setting sales charts on fire. So it's doubtful they would raise the price of all big budgeted games to 60$ even without consoles as very few games can get away with this price point on PC.
Not really sure what your point is. I feel like we are saying the same thing. I am essentially adding that console sales have a halo effect on multi-plat PC pricing. Without them, you wouldn't be getting Watch_Dogs or Assassin's Creed 4 on your PC for $15 bucks in January. I do agree that PC-only non-AAA ecosystem is healthy, and Steam/DD and the PC model enables that.