It is vastly underpriced for the hardware it gives. Some is paid upfront and the rest is paid in data collection etc from facebook.
They have a "unconnected" version for sale for 800 USD and a service fee of 180 bucks. You can see how much you have not paid for in those prices when you go with the ad version.
If the Quest 2 was not associated with facebook I would have owned one a long time ago.
That pricing isn't for an "unconnected" version, that's for a business/enterprise version and yearly support. You can't use that figure and directly convert that into a value you place on your data or ad revenue.
Your point still stands, the Quest is heavily subsidized by user data on the premise of future ad revenue. This has been a given from the moment Facebook decided merge Oculus and FB acounts into one. I'm just correcting a false assumption that the $800 model is just "Quest -facebook", it's not.
But I paid for my Oculus Quest, and then I just paid for a game. I do not therefore want my eyeballs rented out.
Edit: I'd also much rather the Quest platform not become the cesspool that is the free-to-play ad-infested world the iOS AppStore has become. Please can we emulate the Nintendo model and encourage quality games you pay up front for.