I think it ought to be....but it depends on the individual as to whether it is comedy or not....some shows over here I do not get and some British shows it seems Americans do not get....horses for courses I suppose.

In theory, yes, but with film or TV comedy the clothes, etc. can date it somewhat, which is one reason why radio comedy lasts so well. I think Fawlty Towers is one of those rare TV comedies that's timeless, and I can think of a number of radio shows I still find funny long after they were made.

Generally the best comedy gags don't involve mentioning celebrities-of-the-moment or recent (non-important) events. The comedies that reference pop culture of the time make themselves dated.