Let's face it, a 28 minute runtime you can spend quality time writing the jokes, when you get to 1 - 2 hours of air time you need a lot of material, it seems the most logical as to why a lot of comedy movies are a let down compared to the traditional TV series.
Having said that, The Inbetweeners mob did a good job, it's just much harder work I guess... Simon Bird is underrated to be honest as a comedian.
It's a totally diferent style as non-stop jokes are wearing.
You have to factor in new audiences and quickly wrap up plots and relationships we're used to seeing develop over weeks/months. So getting the balance right between establishimg characters and fitting in jokes is quite hard it appears.
What's the question? Are there funny movies? Yes, is the answer.
I agree. If I had to list my top 10 horrors, dramas, action, thillers etc it would made up almost entirely of films. But with comedy, it would be mainly TV stuff.