I wouldn't mind having the option to go longer, but, it's mainly time management. YouTube is one of the few video sites left that welcome gaming videos. Most of the rest forbid them as part of their user policies. Also, I don't want to spend more time on these than I am already. It's a fun hobby, but unless I find a way to make money doing it, I need to stay reasonable in terms of time commitments.
And yeah, nothing worse than to see some dude waffling on just to fill up a time slot. Not my style.