Isn’t it just the cycle of tech captitalism? Build a product that pleases users, make it spread far an wide at a loss fueled by venture capital and hype, and then when you cornered the market, there is nothing to look forward to. No more insane year by year growth in traffic or users because you are limited by the number who realistically will sign up. You can no longer promise growth so you have to promise ever increasing profit, and then it comes to light your premise was never very sound to begin with. Youtube costs too much to keep running with the original idea, Reddit has lousy data gathering opportunities because they can’t couple anonymous users to real people, There is no reason to even visit Twitter because you’ll read any tweet worth mentioning by the thousands of sites who are built around taking tweets and writing articles about it, without all the overhead of actually supporting the Twitter infrastructure.

They are all decent ideas if you want a lot of traffic, not so much if you want to monetise it.

Microsoft doesn’t belong in this list because they can honestly do what they want with their end user product, they have the office space cornered. The minimum requirements are so easy to bypass they might as well not exist. It is just a way of being able to cut down on the range of hardware they need to support. They have Azure and Microsoft 365. If they could ditch Windows completely while keeping companies glued to those two they would. Windows desktop sales are small change in comparisson.