Sonic Hurricane is known for making amazing combo videos. As crazy as these combos can get, you may have noticed that none of them generally do more than 75% damage.
This is due to the damage scaling system built into the Street Fighter 4 series of games. The first hits in a combo do full damage. Damage of successive hits is reduced continuously reduced until hits do almost no damage, which limits the potential impact of massive combos.
Sonic Hurricane has written a great article on the role and importance of damage scaling. Here's a sample:
We can all agree that practical touch-of-death combos are generally detrimental to game balance. There need to be fair limits on how badly a single minor mistake can punished. The price of whiffing c.MK should not equal the penalty for whiffing an ultra. Furthermore, characters possessing the best mobility and the most offensive mixups probably shouldn’t have the highest damage potential.
If you don't know what "touch of death" combos are, click here for the IPW glossary entry.