Do people who have surgery for crohn's usually live longer than people who don't have the surgery?

Not neccasarily: It all depends on how well the Crohn's is controlled either medically or surgically or both.

yes: Better stated, people who need surgery for crohn's and have it live longer than people who need surgery and don't have it. Now, people who have aggressive disease are more likely to need surgery, and may have a slightly shorter life expectancy.