That’s something I think should be looked into by FIFA at some point, the salary and cost of a player although, this has been some worth regulated in the amount a team can spend in the transfers but, over again, you find teams seeking loopholes and cutting corners to archive their goal of getting what player and under certain conditions.
Not like situations in the society have helped much but, the cost of a player could be capped as, every transfer season, it often seems like teams are in the rush to hype the cost of a player who only turns out to deliver on few occasions.
Such financial regulatory laws exist but it is not handled by FIFA. Uefa's Financial Fair Play regulations were established to ensure that clubs don't spend more than what they earn and they are mandated to balance their books every three years. The main challenge in implementing this law is the presence of wealthy club owners who use personal funds to invest in players. The FFF regulations will always be bypassed because clubs are always desperate to sign good players.
Having restrictions that mandate you not to spend more than what you generate could be seen as having a benchmark (capping). We know that some players are exceptional and they are worth more than others. It was the likes of Roman Abramovich and Sheikh Mansour that inflated the players' transfer market and today we have players whose buyout clause is half a billion dollars. I think UEFA should step up the implementation of the FFF rules to enable poorly funded clubs to also participate in the transfer market.