I can dig what you're saying and if we were talking about any other company than Nintendo I would entirely agree with you. I've got nothing that would validate my opinion or anything like that, but I hang on this paragraph above. I think that when it comes to Nintendo and third parties, there's another factor, less tangible, that plays a role just as important as the real honest to god factors you listed. I think it's this factor that caused many companies to say, "We'll wait and see what's going on with the market before we commit" even as the Wii was exploding on the marketplace and conversely, "We're very anxious to get our software on the PS3. Lower the price Sony!"
I guess where our difference of opinion really lies is in the presence and nature of this 'x factor'. I think that nearly all aspects of the market's behavior can be explained without resorting to this 'unknown'. For example, the attitude you describe in the last sentence is a clear result of pre-launch investment in PS software development projects. If PS3 didn't succeed, the bets they'd already placed wouldn't pay off.
You've been around so you know I'm paraphrasing the market currents of prev gen launch, but I think it illustrates my point well enough to give you an understanding of where I'm coming from. If we'd seen at least some follow-ups to early successes on the Wii, I'd be more inclined to not spiral into this weird area of discourse.
I'm certainly not going to praise the third party treatment of the Wii and its audience, because when they did decide that the Wii was worth betting on, they made some really bad decisions about
how to bet on it, managing to significantly alienate the audience in the process. Not to shit on shooting gallery games, but by teaching the enthusiast audience that that's all that Wii's asymmetric control advantage is good for, they squandered a lot of its potential. Of course, Nintendo missed many opportunities in this area as well, so there's that.
May as well add to what I edited in above while the thread is slow. I think the odd thing here is how long it actually took for the PS3 to become a viable platform. Beyond that, I don't think the PS3 would have even eventually become a viable platform without a good amount of the industry really pulling for it to happen. I definitely understand the ps3/pc/360 as one platform as an argument, and I think it's a good one for the latter half of the generation. I just think it's important to understand how it eventually came to be that way cause it sure as shit didn't start that way.
Sony managed to price-correct before the attitudes of pre-launch investment evaporated entirely, providing it with enough users to fully participate in the dominant mid and late-gen development and publishing strategy. Wii's late-gen slump didn't need to be as bad as it was, and Nintendo and third parties can both be blamed for this, but it was always an inevitability that 360 and PS3 would end the generation as a superior platform for games designed primarily for a dual-analog control scheme.
One other thing to consider is that while third parties are relatively hungry for a hardware refresh, Microsoft and especially Sony are hungry for another fiscal year where their console business is in the black. Neither of them are providing the kind of evangelism that existed in '04-'05, so third party publishers are left making a much more diffuse and platform-agnostic bet on the next generation. While they have little pre-launch incentive to heavily support the U, they've got no reason to leave it out in the cold unless Nintendo gives them one.