I think you possess a fundamental misunderstanding of why this is happening.
> If management consistently can't find a way to make that level of revenue without spending far more each year then yes it's not a real business.
Could Twitter fire most of its developers and sustainably turn a profit? Yes, it absolutely could. Hell, I could do that. "Sales people, keep doing the same thing. All this other expensive overhead is gone." But instead the executives choose to invest the company's would-be profits (and a little more) back into the company, in hopes that they will be even bigger later on. And they're still growing (at a rate faster than expenses are), even beating analyst expectations to this point. The stock drops because analysts are concerned this won't continue to be the case (Wall Street is weird).
In a very real way, the only time big tech companies start turning a profit is if they think they are reaching the peak of the revenue they could generate. Until then, it's time for growth. That growth is still very valuable, they're just hot taking profits yet. http://ben-evans.com/benedictevans/2014/9/4/why-amazon-has-n...
Hence, if you're looking at every company to determine if it is profitable or not, you probably come away with a very misleading, "The world is doomed" view of the economy. Companies aren't taking their chips down yet, because they're still confident they'll grow.
It seems counter-intuitive, I know, but that's the reality of how companies act, in order to maximize the profits long-term.