I don't care about sales parity.
I care about profitable ecosystems that are segmemted, targetable, offers differentiation, and monetizable. That way lots of different content can be developed and tested in given segments for success.
Your goals are eminently reasonable, I'm simply not sure you've convincingly demonstrated exactly how "one console sells much better" wrecks those goals. For example:
If a console sells 50MM and another 30mm, and I can release a shooter on one and a platformer on the other and both make money, how is that not great for everyone? I can diversify and spread my risk, and consumers get more genres targeted to their interest because its easier for Me to find You.
In the bolded parts, who is "I"? If a developer, don't the vast majority of them actively work on only one title at time (with others in concept or prepro stages)? If games are developed sequentially, there's no diversification possible.
If on the other hand you mean a publisher, then diversification only requires multiple machines if the market is rigidly segmented--that is, one console is the "shooter box", one the "kiddy box", etc. But why should we expect, or desire, that different audiences stick to disparate hardware? If one machine outdoes all its rivals by selling to male shooter fans
and families
and aging retro fans, etc. then why can't the diversity of games flourish there too? Here's what I mean:
If you had one box and it was 80mm, my shooter has to compete against s million shooters.
Sure, but how is that improved by having a segmented "shooter box" with a 50m installed base? Everyone making a shooter will target that machine, so how are you facing less competition than the 80m console with 50m shooter fans on it?