Throttle mode is there for those that want a major challenge.
Generally, it's for people who play alot of shmups, and are very fast.
I personally dont find it THAT hard.... I've played ALOT of shmup games, and I am very fast. And I love a challenge. My usual score in Trottle for Deluxe ends up being somewhere around 7000-8000, if Im paying enough attention. Right now, my highest is about 10100 (throttle mode, for Classic, on Deluxe, I'll work on Asteroids Normal later), can be seen on the leaderboards. And I've only been doing this for about an hour.
Games of this type take PRACTICE, and usually lots of it. I can do this cause I've played games like this to death. You gotta be ready for LOTS of repetition, if you wanna get good. That's just how this genre works.
Besides, if you dont like Throttle mode..... and not everyone will..... just dont play it! That's what the normal modes are for. Those are the ORIGINAL versions of the game anyway, which is why you bought it, right?
EDIT: Oooooooorrrrrr, the damn score that was there 5 minutes ago is suddenly gone. Fah, that means I have to do it AGAIN. That's just a BIT annoying. Thank you, Microsoft, thank you very much.
EDIT AGAIN: Ooooooorrrrrrr, it IS there. Feh, probably just my modem or router being SUCKY again. Note to self, replace that dang thing. Hate it.