There are some interesting replies there. And some other comedies mentioned, in the long distant past, convinces me even more that sadly there is a lack of good, new material out there. I do agree about the ad libbing, or lack of, they made a comedy sketch that more entertaining. The actors usually crack up in fits at one another, and that spreads to the audience, an altogether more atmospheric experience. Sadly not seen anymore.
I don't think it's necessarily about money, afterall, it's not as though there isn't money being spent, there is. Comedies are still being made (although not in plentiful supply), there just isn't the quality IMO that they once were.
Thinking more about this subject, makes me wonder about the kind of material that is being written. There does seem to have been a snowballing of being politically correct. It seems you need a law degree these days, knowing what IS and ISN'T politically correct for a comedy. There's no way, in this day and age, that writers can get away with anything that will "stir" up racial tension. What about shows like, Rising damp, Alf Garnet, Love thy neighbour (who remembers that one lol). although admittedly, Rising damp has been re-run recently on ITV. The thing about those comedies was, although they had racist characters in them, it was usually the racist that ended up looking the prat lol. And they were hugely successful. Maybe that's the reason there is a lack of good material now, writers hands are being tied because of political correctness. They do, afterall, appear to be running out of idea's.