I mean Guardiola mooted that a player strike might happen on this issue about a month ago. It was certainly an issue in the last pfa election https://www.bbc.com/sport/football/59347490.amp
I suspect the problem is ultimately for competitive animals - which the top players are. Refusing the opportunity to play goes against their nature. All players are drilled to seek out and seize opportunities for first team football. You don’t make it out of the academy (and the majority of people don’t make it as pro footballers) to the first team if you don’t have an insanely professional mentality and strive to play every minute you can. A lot of players would fear being dropped permanently if they asked managers for rest or getting benched by a sub or rotation option impressing when called upon. Pep himself has said he has to rotate purely to keep players happy with their minutes. Zidane spoke about how difficult it was to convince Cristiano Ronaldo to sit on the bench even if it was obvious that as a guy in his mid 30s his career would be longer and better if he missed the odd game where he wasn’t needed like a copa del rey tie vs a 3rd division side or a UCL group stage dead rubber.
This factors into the other issue. It affects such a small proportion of the players. The vast majority of professional players play outside the top leagues and top divisions and therefore don’t play anything other than league and cup games and don’t get called up in international breaks. Even in the premier league the majority of teams don’t play European football, even amongst those who do play in Europe there’s no guarantee they go all the way to the final every year. Even on the teams who can guarantee that (basically just Man City) they have a deep bench and rotate - Haaland and Rodri are the only guys who play every game for their club and their country when fit. For the majority of players who the unions represent they want more game time not less. There are far more players in the situation of (picks random cb) James Tomkins who plays every now and then for Crystal Palace so is rarely playing midweek and always has the international breaks off than Virgil Van Dijk (in the same position) who plays pretty much every game as Liverpool captain regularly making deep runs in both cups and Europe every season so playing multiple midweek matches and captaining the Netherlands every international break and 2 summer tournaments in a row.
Most players have Tomkins match load not Van dijks
I’d say Americans are still very much not considered good technical players. With the exception maybe of Reyna at Dortmund, the best American players are very much good at elements of the game involving, pace, physicality and aggression rather than what to do with the ball at their feet