I don't disagree with OP's point, but I don't think he does a good job at making it. He name-drops several popular startups that were bought out then implies they wouldn't be bought if they were making more money.

Etherpad, for example, charged for it's product. You could use it for free, but if you wanted private pads and custom domains/urls you could upgrade to Pro. I don't see how "doesn't have a business model" applies to that.