Low profile tires last between 20,000 to 40,000 miles depending on how you drive the vehicle and how you treat the tires.
If you do burnouts or spin the tires or drive fast a lot then the low profile tires will not last as long than regular tires do.
Low profile tires do wear out faster than regular tires do.
The low profile tires grip the road better and they have more pressure on the road so they wear out the tread faster than regular tires do.
Your driving style will also factor into the lifespan of the low profile tires as well and the faster you drive the shorter the lifespan of the tires.
Low profile tires also seem to provide better gas mileage according to some people where I've read on car forums.