Ccomedy and Timing.
In the 70s Bernard Manning was on prime time television. He was very funny, a good comedian, but his act was highly sanitised for an ITV Saturday Night Viewership.
After a few seasons of very good ratings, 'The Comedians' was deemed old fashioned and cancelled. It was never banned or taken off because of the PC Brigade, it just didn't reflect how television wanted to portray itself.
When people who had seen Manning on TV grew up and went to see his act, it was bluer, cruder, and more rique than they had seen on telly, and they liked it. It became a cult, and his stature grew.
Is Frankie Boyle the new Bernard Mannning? - no he isn't. For a start, what is allowed now on TV, and the internet, would make Bernard Mannings hair curl (if he had any).
Unfortunately, in the past, if a TV company got into trouble with an offensive Manning gag, it was deemed bad and people got into troubled, and maybe people in charged got sacked, or at least got their pay docked.
Today, they actually court the headlines and the bad publicity because it gets viewers. Today, the more offensive, sick or disgusting the better. If you can attain that, The Daily Mail will make sue you get the most pubicity than in your wildest dreams.
Saying all that, I find Frankie Boyle funny (though I haven't seen any Tramodol Nights).