Some of the criticism has just been that there's kind of a category error being made: not that these aren't good businesses, but that they aren't really tech companies, and calling them "tech companies" is more of a PR move. For example AirBnB is a successful business, but very little of its success has to do with technology it builds. It certainly operates in a field shaped by technology, and does need some amount of technology to operate the business (a website, some billing infrastructure, etc., roughly technology on par with any airline or hotel company). But, like Wal-mart a generation earlier, its success comes mainly from noticing that ongoing changes in technology and purchase habits open up new kinds of business opportunities as a specific kind of intermediary, and pushing hard to exploit that market opening.

Craigslist is perhaps an even more pure example of that, a "technology company" where having almost no actual technology, beyond the very basic level of "a webpage", is kind of their ethos.