This happened to Yahoo too. They were quite happily tooling along, making profits, building cool stuff, and employing people with remote-work policies, small-biz tools for folks, and what-not. Then along came an activist investor who turned it into a royal shit-show.
He finally convince Verizon to buy it, but man it was a wild ride. I don't know if it made the investors money, but it made a lot of people sad.
Even if I was an inventor that wanted to build one of these things for no personal benefit, until it was profitable (under some business model), it could not sustain without the goodwill of grant-givers or the greed of investors that knew their money would be returned to them under some sort of risk-adjusted time-based return calculation.
In other words - who can afford to do something like this for free? (Now - I am not a fan of Twitter, so if the answer was "no one", it wouldn't hurt my feelings, but I guess some people think that it is important somehow?)
Couldn't/shouldn't Twitter's mission be to distribute 140 characters from one person to many others...what do they need huge revenue and profits for?