Youtube is a great website with Ublock (or premium, I assume). It's borderline unusable without, which is why people are so reluctant to shell out for premium - the ads feel less like a reasonable attempt to monetize, and more like an attempt to push people to premium.

Because it comes configured on your phone or browser, and learning to use new tools implies will and effort.

Your non phone computer comes with Edge/Safari, yet most people use Chrome

Because Google pester you constantly to install it.

Inertia, convenience.

Network effects.

Network effects are good for the creators who make it big.

Is there a way to build a recommendation engine with a distributed system? Or a search engine?