The 2-3 minutes is really quite standard. And even that can feel like a lifetime when you're watching a skit that drags. Of those, I have seen plenty. I can't recall a single skit I've ever seen that made me think "Wow! I really could have gone for another minute or two of that!"
If you think of the skit as, say, a commercial or movie trailer or something, then it's plenty of time to get a message out there. Musical skits can always trim out verses or repeats of the chorus, comedic skits can trim the less funny parts and leave on a strong note, and dramatic skits... well, those are tricky and hard to make generalizations about, but you can always make cuts.
That's not to say I couldn't fill 5 or even 10 minutes with material; I've got some skit ideas, even scripts, that run way the hell too long right now. But I know there's superfluous material there that I can get rid of, it's just a matter of identifying it. Sometimes I get really attached to certain elements and need a fresh and impartial pair of eyes to look at it and tell me what's not working, but there's always something there that doesn't need to be. In general, 1 minute is actually a lot of time, and most things can (and sometimes should) be crammed into that time limit, but it's great when masqs give you some additional time to play with and expand on your idea. I generally aim for about 1:30 with my skits, no matter how much time the masq is willing to give me.
The real problem is that longer time limits generally make people think they need to use all the available time. Even some of the best ideas, stretched into 5 minutes, would get old. The audience doesn't need much time to get the gist of your skit, and if they like it, the remainder of the time can be fun, but you risk losing them. And if it's ultimately not to their taste, the remainder of the time can be torture. So it's probably best to minimize the remainder of that time.