If you are not paying for the product, you are the product.
The internet culture birthed from the early days of the internet "Everything is free", seems to have captured a whole generation who simply have no concept of cost and value.
Vid.me is another start-up that comes to mind: Youtube sucks, has too many ads, and sells your data. We won't have ads, won't sell your data, and will host all your content.
It made it four years before investor cash dried up and they said goodbye.
That's a fun quip (and often correct) but the world needs a way to run this kind of project. Community? free? transparent? etc, etc.
And I think this issue is not just about "free systems", culture changes and day to day corruption creeps and destroys everything. Even die-hard for-profit institutions (where entire branches might go rogue on their own objectives.)
A sandwich costs $5 everywhere, and a car costs $30k everywhere, because that's just what those things cost to make.
It's relatively difficult to look at a web service and determine whether its running costs are normal guy hobby money, rich guy hobby money, or no seriously this won't last six months without VC money.
Decentralised and P2P systems run themselves, but it's hard for them to maintain a centre of gravity without offering something specific, and given that the network itself can't produce value out of thin air, it's probably not coincidental that the ones best able to maintain gravity are offering stuff stolen from elsewhere.
(YouTube, Uber, Airbnb, etc…)
The truth is that a profit-maximising business will seek revenue opportunities where it can, and if that means selling both services, on a single-instance or subscription basis, and advertising, it will do both.
Advertising-only or advertising-dominated businesses have a strong tendency to degrade faster and far more prolifically than those with mixed-model funding (I still find The Economist's three-legged revenues stool fascinating: subscriptions, advertising, and Economist Intelligence Unit bespoke consulting and research services, each roughly 1/3 of total revenues).
Paying alone, however, is a far-from-sufficient condition.