The system set up by F.I.D.E. ... Insures that there will always be a Russian world champion... The Russians arranged it that way.
In chess so much depends on opening theory, so the champions before the last century did not know as much as I do and other players do about opening theory. So if you just brought them back from the dead they wouldn't do well. They'd get bad openings.
FIDE has decided against my participation in the 1975 World Chess Champion title.