If you take the number of 5* players on the market per day, there may be more of them, I don't know. But now, when managers from different levels see the same market, it looks like the players are being sold for much more tokens than it used to be and therefore it has the opposite effect. I would suggest to at least double the number of players shown on the market.
Does the system buy all the players managers try to sell? Because that's how I understand your sentence. If it's true, why the system doesn't buy my 18yo player after I put him on the market at least 5 times?