Question: are some parts in comedy so closely tied to culture and time that they must change? 

Answer: Yes, definitely.  Comedians can do skits that are hysterical and appropriate when new, but 10, 20 years later the jokes are not funny.  Why?  Because the times have changed, people have changed (and aged).  It's like music - a hit is a great song for awhile.  The hit didn't change, but the people/times have.  To stay (or get back on the charts), the song needs to be updated, as does the comedian's jokes, if he wants to stay on top.\n\nAn example of how times have changed, might be George Carlin's "Seven Words" skit.  There "were" seven words that could not be used on television [Da*n, f*ck, he*l...].  But now, a lot of those words are used without hesitating or censorship, and the skit is not funny (unless you remember those days - or Carlin changes his skit to reflect the difference between then and now -- which he has, I believe).
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