I'm not saying they all got together and decided this together but their wonks are probably all saying the same thing. The market is shrinking and whether it's by design or incompetence, this creates a new opportunity to acquire it wholesale for pennies on the dollar and build a wall around it and charge for entry. It's a natural result of games requiring NVidia developers for driver tuning, bitcoin/ai and buying out capacity to prevent competitors.
The wildcard I can't fit into this puzzle is Valve. They have a huge opportunity here but they also might be convinced that they have already saturated the market and will read the writing on the wall.