Superman and star trek are quite different, trek has never been a hit worldwide, it is -like many of you have said- an "american" product, while superman is a world wide icon and the franchise has proven it's self to be a titan in the past (STM has made an excess of 590 or so internationally and while I don't have the figures for SM II I know it's still one the highest grossing superhero movies in places like japan and spain) so the potential for breakout OS numbers are there, just not for a reboot coming off the heals of SR.
I personally think that 270-300 is the most this film will get but if it's received well by the general public with 2-3 yrs of hype build up, the sequel can most certainly do dark knight, spiderman numbers.