A monopoly doesn’t have to be one club, it can be a cartel of clubs (like the big tech companies), in that sense the ‘super clubs’ are a monopoly as a whole in their buying power and especially in each domestic league.Do you think any club has a monopoly? Chelsea aren't even dominant in the market.
I mean, I agree that continued player acquisition might lead to a monopoly, but there are mechanisms in place to break that up.
Now holding colossal squads and subsidiaries is a definite sign of centralization of market power.
ATM I see no mechanism that can break the monopoly group and not just the dominance of a single club