It comes down to the concentration of wealth. Companies wouldn't have the capital to bid up salaries if they faced stiffer competition or couldn't access investment from a limited pool of investors (who all think the same), as is the case now. I know that "diversity" is a dirty word these days, but it's key. A large middle class, where each family has a small amount of money to put towards their diverse desires, is going to lead to a more stable economy than all of the money pooled in the hands of a small group with a much smaller set of needs. Dropbox should never have been able to hire so many people; that capital should have been in the hands of the larger public, who could have spent it supporting a more diverse set of hundreds or thousands of jobs (who wouldn't all be competing with each other for a limited number of seats in the "not laid off" lifeboat).

Put simply, these kinds of things are going to keep happening until our wealthiest (individuals/families/companies) are a lot less rich.