In software development, 1.0 is the version number you assign to what's ready at the end of the last day you are permitted to continue working on your release.
Before online gaming, games were required to deliver a 1.0 and had no further chance to patch or improve it. They would do so in silence — like Nintendo does — and essentially work for years on things that no one even knew existed until they released their 1.0 gold master and began producing marketing material from it.
Nintendo continues to follow this policy today — we get demos when they've finalized the game, and not before — and Nintendo refuses to market games until they've finished them, so we get years of "will there ever be another Super Smash Bros" and "OMG TELL US WHAT'S COMING" which they silently ignore.
Now you declare openly that game developers who tell us what's coming while it's not yet finished will be punished if:
1) What's not yet finished doesn't match what's finished on 1.0 day in any way that is personally meaningful to you and/or anyone;
and/or,
2) What's announced is announced only with a complete finished 1.0 product from which marketing materials are exclusively developed and provided immediately upon announcement.
So, you're championing the Nintendo model, which is fine — we will hear nothing about any upcoming games until they're ready to be released, and if that means years of silence from the owners of properties such as Halo, GTA, Pokemon, and so on — then that's completely acceptable and we should expect to hear no complaint from the gaming community as a result.
I am not led to believe by your response that "we will hear no complaint" is the outcome that will occur if and when the entire gaming industry complies with your demands by stopping all pre-release announcements altogether, which leaves me wondering: How, precisely, do you expect a valid outcome to occur from your requirements that both satisfies your demands without triggering complaint over the lack of updates over time from studios who are busy complying?
EDIT: To pre-address the most obvious reply — "they should only demo what's done" — I guarantee that nothing is ever done until the final day of development, as critical features can be cut literally hours before gold master if there's an undiscovered flaw that QA discovers at the last minute — so since "nothing" is ever done until the final 1.0 release, "they should only demo nothing until the final 1.0 release is done", and we're back to the above question.