Companies should be built with revenue (and profit) in mind, and in most cases those are the ones that thrive and succeed.
During the "unicorn boom", I think we all had this belief that network externalities were very common in tech - a belief driven by the rise of facebook, google, and others. But now we're realizing that maybe strong network externalities are just as rare in tech as they are in other industries - and a business without network effects that's losing money for growth is just a business that loses a lot of money.
This NYT article from last week seemed to do a good job summing up the issue: http://www.nytimes.com/2016/02/13/business/dealbook/the-rise...
It now seems that we may have overvalued this effect. In fact, startups can grow quickly because new tech makes the first mover advantage tenuous; why should the effect that allowed us to climb the mountain now prevent others from doing the same?
The classic Metcalfe's law stuff means that a messaging service or marketplace with more people is more attractive to users than one with fewer, but not that those users will spend significantly more money or time on it. Certainly not linearly more.
How does the number of Uber cars in a city affect the frequency with which passengers use them?
And how many network externalities are there that don't rest on advertising dollars?
I've always perceived startups to be some kind of an extension of these (highly questionable) concepts and principles into the tech space. These days, it sems we're drawing closer to witness a clash of this weird, bubbly universe of its own with the real world as it were. The only real questions about it, I think, are: when _exactly_ will it happen, and what will the fallout look like?