Neither revenue sharing nor a minimum and maximum wage cap would be impacted by the world markets.
Different leagues already share different % of their revenue with the PL’s old 1.4:1 ratio of money being given to #1 and #20 often being cited as a reason for the PL’a growth, and the PL is so rich that no one can compete with its maximum salaries outside 4 clubs (Real, Barca, PSG, Bayern) who all face their own limitations.
I like the MLB/NBA system where there’s a max cap and for every penny you spend over that you pay a tax.
So set it at say £300m wages and/or £100m net transfer spending per year, if we want to have a squad earning £400 and spend £300m in a window, we can, but we have to pay a tax, and that is then distributed to the other teams.
You put all the money spent by all clubs over the maximum into a pot. Set up a scale so the money is distributed primarily to the lower table clubs. For example clubs 17-20 get 9% each, 9-16 get 6% each, 5-8 get 4% each and 1-4 get 1.5% each. Those numbers were off the top of my head I’m not sure they even add up to 100% (doesn’t have to, you could allocate 5-10% of the total to the football league or grass roots). Someone much smarter than me could work out the perfect splits.
You’re still allowed to spend what you want, but you’re not incentivised to spend significantly more than your opponents, because you’re just subsidising them.
And because it sends so much more money to the bottom of the table it allows you to raise the minimum spending, increasing the average quality across the league and narrowing gap from #1-#20. Imagine if Luton, Burnley and Sheffield United had an extra 30m each to spend on players, would they be so far away from the rest?
It also means that owners would be less fearful of super rich new owners coming in. PIF spending £1Bn over the next few years isn’t so scary for American owners when they are paying you for the privilege.