Umm... I can think of tons of franchises where the first in the series wasn't much, then later games exploded in sales/popularity. How about:
Street Fighter 1 vs. 2
Grand Theft Auto 1/2 vs. 3
Call of Duty 1/2/3 vs. 4
Mega Man 1 vs. 2 (for the old-timers)
And that's just off the top of my head. Really, it's not THAT surprising. If you give a development team unlimited time, employees, and money to work with - yeah, they can probably turn out an improved game.
End of 2008 totals: Wii 42m, 360 24m, PS3 18.5m (made Jan. 4, 2008)







