A lot of the writing team went on to bigger things: Armando Iannucci, Patrick Marber, Lee and Herring (if you believe they created the character and their feud with Marber was fucking hilarious), Peter Baynham who went onto work with Sacha Baron Cohen on his films, David Quantick who I think fixes scripts more than anything, but has worked on some crackers.
Speaking of BBC nurturing talent, they seem happy to show Dad's Army, but won't even mention It Ain't Half Hot Mum which was by Perry & Croft and probably a bit more personal to them.
Dads Army is perhaps a bit safer and has a lot of sayings still used quite commonly like the classic "Don't tell him pike", Corporal Jones making reference to Fuzzy Wuzzies a few times is possibly the only thing which people may be offended (or choose to be offended) by.
It Ain't half hot Mum had continual references by Windsor Davies to them just being "Poofs" which TBF probably hasn't stood the test of time and would no doubt shock and enrage people in 2021.
And then of course there is also Michael Bates who blacks up to play an Indian character Rangi Ram which would probably kill off a few snowflakes
As already mentioned there are some classics mentioned here such as Dad's Army; Only Fools & Horses; Porridge and The likely lads but no doubt there was also a lot of long forgotten crap produced too before the diamonds shone through.
Not sure about the others but Dad's Army almost didn't get made as the pilot bombed in front of an audience who simply didn't get it, strings had to be pulled to actually get a series made.
Think it was similar with Only Fools which struggled to get a 2nd series and I don't think was actually that popular to begin with but once the ball got rolling it just gathered speed, Lovely Jubbly