I suppose they might be regretting the split nowadays. The whole vertical-integration thing is coming back into fashion. That type of governing body exists in other areas, golf's governing bodies have been a little more separated than some.
I wonder if a fully vertically-integrated structure would be of any benefit e.g. people who make a living from the game? The other sport I follow more closely is F1 racing, whose governing body, the FIA, is like the international equivalent of the American Automobile Association (AAA), here in the states. They run F1 (and other FIA racing series) but also care about general road safety and training while also licensing race car drivers. It would be like if the USGA, PGA, and Tour were a single entity. It's more complex than that with a separate commercial rights holder, but that's the basic drift.