It was once thought to be, but still no. Only in Fifa 99. I don't expect to see this because it would be completely bad for small countries.
Unbalanced situation came after Bosman and EU directions to allow EU members to move freely where they want.
Players have become employers, not sportsmen or sort of specific occupation. By using that definition, football has become officially a business. 8+3 rule was broken by EU(not Fifa/Uefa) and you couldn't do anything about it.
Abramovič, TV revenue, sponsorships, everything large has come in football after that. Cause was the death of 8+3, the result was Premier league with 1/3 English players, no domestic managers, no more domestic club owners, historic Arsenal first eleven 10-11 years ago without a single English player, etc.
Sort of trend moved to Bundesliga where more than 51% of players were foreign nationality, but after both Euro 2000 and 2004 they decided for 50+1 rule, lower restrictions from 5 fgn to 4 fgn, invests in youth setup on both professional and amateur level, infrastructure, coach schools, etc. But they still can't get closer to England and Spain on domestic competitiveness, tv revenue, huge transfers(Bayern is the only expecption)
13 years ago I was strong supporter of bringing back 8+3 rule, but it was impossible. Neither 6+5 which Fifa suggested couldn't pass in EU. I gave up in 2007 after I saw that there wasn't another way we can get closer to PL and Primera clubs, Milan and Inter and then we spent 70 mil € for the first time in our history in one transfer window.
We wouldn't do that ever if there was the other way, but there wasn't.
The rich have become even more rich and dominant, the rest can only depend on good luck with generation of talented players, great directors of football who can sell for n-times bigger sum of money, scouts, etc. or just find a people like Klopp and Simeone who can with less resources build up a strong team in 3 years.
This battle for "football" was lost in 1995-1996, ie 18-19 years ago.