Jim,
A few points here:
I don't know if we could call bowling a major sport, but yes they do use their own balls. That being said there isn't much variance between venues other than lane quickness and oil patterns...
Other sports were more "individualized" before the leagues took over.
- Football being the glaring example, kickers often had thier own balls just for kicks and some QBs used thier own methods to gain advantage!
- Baseball teams used to manage their own balls as well. Some would soak em in water to deaden them, others would bake them to make em harder before the league stepped in.
- Even the NBA has tinkered with composite balls that all the lower leagues (college, high school) use, before going back to the all leather ones.
On a higher level philisophical view, all professional atheletes have to make various changes and adjustments when going to the pro version of thier sport, so going to a new ball for golf wouldn't be anything new or unique. With so many advantages, and so few disadvantages, I'm partially surprised they haven't already done so.