First, I hope that Apple begins to release more movies on Tuesdays because I like the whole service thus far.
Onto the main point. Your point about Stick-It is quite valid and very true. What you have to factor in is that like music, Yanni's greatest hits will sell maybe 5000 copies in two years whereas Yanni's Greatest Hits will be downloaded 5000 times in less than a year on iTunes. Why? Because iTunes has allowed us inner Yanni fans to buy the music without having to show our face. The same goes for Stick-It.
I use Blockbuster Online Rental service. I have rented more movies that I would not buy or rent in public than I care to mention. I am not talking about porn either. Things like "She's the Man" or "Confessions of a Teenage Drama Queen." I've rented, watched, and returned as though it was LOTR or something very "cool" like that. Faceless renting and now faceless downloading has given people who maybe wanted to see that kiddie movie Stick-It in theaters due to the fancy one-liners they show on the previews and chance to see it and own it. Perhaps there is some 30 year old watch 20 year old girls act on the big screen and play parts of 14 year olds (ie: Dawson's Creek) and they find this entertaining and they enjoy the acting. Whatever the reasons, iTunes gives people faceless downloading of crap you would not normally admit to liking. You do not have to buy 10 punk CDs and shove in one show tunes CD and get glared at by the teenager at Tower Records for being a sell-out.
This mentality runs all over in many different contexts. Such as people who buy more food than they know they should. Two burgers and two fries and then they figure it'll somehow look like the food isn't all for them if they buy two sodas. I know this happens because I used to work in fast food and I'd see someone with a bit more weight on them than necessary and they would buy two entire meals and when I would go out to toss some trash or whatever I'd see them around the side eating...alone. Music, movies, whatever...it's all the same. How many people over 21 want an Elmo TMX? I know I am and I do.
iTunes is giving everyone the chance to resurrect their inner geek.