AOG, when you were young, did people made jokes about Jews, jokes based on a stereotype that Jews were cheating or dishonest, inter alia? They certainly did in my time. Wouldn't those jokes would be found a bit too much for you now to laugh at? Indeed, they used to make jokes about Scotsmen; whatever happened to those? The demise of these could be 'political correctness' were it not that the term hadn't been invented, or made popular, at the time of it. The world had changed.
Jokes based on the colour of someone's skin or supposed characteristic of their race; what in the old days were called 'sambo' jokes; persisted longer. Jim Davidson had an act which was largely based on the stupidity or accent of his fictional black West Indian friend. The 'stupidity' jokes might have worked were the 'friend' white (Policeman to man " Your rear light isn't working" Man kicks rear light; it works. Policeman "Very clever. Now go and kick the tax disc ...") but the audience found that the racial element made it funnier, which Davidson depended on.
Your premiss that old shows would attract the same big audiences as they did, depends on the modern audience being of the same as previous ones in finding them funny . Tastes and times change. To the extent that the shows depended on skin colour or supposed racial characteristics, or homosexuality, they would not to be the taste of the modern audience any more than jokes about cheating or dishonest Jews would be.