I don't see this as an old Vs. new argument so much. As I said, my nephew loved the Ed Sullivan skits. They were fun, funny, entertaining and could be appreciated on many levels.
This is also true of GMC, but IMHO that movie has too many places where the script carries the humor and not the visuals and for youngsters I think that can be a problem.
Add in the fact that today's kids are brought up on a diet of farts and pratfalls in quick succession and the problem is exacerbated. The reason Sesame Street isn't shown in the UK is because TV Execs don't believe kids will watch an hour long show any more. This is partly the reason Elmo's World was added I believe.
We can keep wishing it's not so, but it doesn't make it true.