Apps is used internally at Google, as I understand it. That's where many of its component applications were first used -- a real case of dogfooding (and/or commercializing what you're already doing, à la AWS, for example).
They recently whacked multiple child accounts for what was Apps Standard / "free".
They also have long term contracts, e.g. with the GSA.
Maybe they'll tighten the screws on commercial Apps accounts/availability, but I don't really see Apps going away anytime soon.
Which isn't to say one shouldn't back up, and be prepared.
If they kill Google Docs, etc., will people move back from the cloud after loosing everything?