I can probably help with some of the explanation on this. Not necessarily the data stealing side of things but definitely how they killed off competition. Youtube operated at a loss for a looong time while providing a stable and well functioning platform where creators could make a decent amount of money this resulted in year over year userbase growth. This not only made it harder for other platforms to break into the market as no creator would want to spend time making content on a platform with less users but also the other platforms did not have the capital behind them to operate at such a loss so they die out or they get purchased by google/youtube for a bargain and get shut down. Now youtubes userbase is so captive that they are pretty much free to essentially abuse their users almost as much as they want because as a viewer theres not really any other platform out there that has the creators you watch and as a creator theres no platform thatll get you enough views to be sustainable. Its a cycle that has to be kicked off by something big like youtube going down because thats the only way users are going to migrate.

You kind of see something similar with big box stores, companies moving into areas or even just gas stations. Big gas station companies arent in the gas business, they are in the real estate and convenience store business. They often sell gas at a loss even though they have their own fuel logistics supply chain. Other stations who rely on income from fuel sales and less so convenience sales struggle because they cant secure the selection in the store and dont have their own fuel logistics. Many go belly up unless they have something unique that keeps people coming in like restaurants or a unique drink selection. Once most if not all the local stores go out of business then the big store prices rise and the consumer is abused.

Google has stated that theyve operated youtube at a loss for a very long time but (and this is my speculation) its been done intentionally to edge out the competition and retain sympathy from its userbase to justify the abuse. Youtube is making massive revenue but they are spending it. If google/alphabet didnt see it as a profit stream it would have been killed a long time ago. My theory is they are sorta playing the game from both sides and overspending on overhead and padding the execs wallets more and more just to tell investors and shareholders that while revenue has increased, so has overhead/labor/etc just to take home their own fat paycheck while also milking their userbase for as much as they can. At some point its gunna break but execs have already made out on their goods. Yes video hosting and platform development is expensive but I do believe youtube is not spending most of its money there and that it doesent need all the overhead spending think of how crappy their content review system is. Nothing gets seen by a human except in very specific circumstances