You are missing out some important nuance there: no one said it would fall off the earth immediately, that it would cease to function right now. Many, myself included, have said we think it can't function long term, or even medium term, like this.
Day to day running of the main app is all automated when things are OK so it will keep ticking over as long as someone says the infrastructure invoices. The real test comes when there is next an infrastructure issue or some other fault: are the right sort of people there to resolve it quickly? Also do they have a good combination of people around to work on those bugs those advertisers are concerned about and other maintainence & improvement (of both the app and the other infrastructure it and the company relys upon)?
If we get rid of all car mechanics your car won't break down immediately, but good look getting it sorted easily when it eventually does develop a fault.
Twitter was somewhat bloated, I agree there. But what has happened to it in recent weeks is far more damaging than that could ever have been. It needs to turn around very quickly to survive financially and technically, and I think the chances of that happening are small.