Dan:
The number of golfers who play the USGA and/or R&A rules are not just a minority, they are a vast minority. At any given golf course anywhere in the U.S., on any day except tournament day, there are as many sets of rules being played as there are golfers on the course.
Part of this, frankly, is the fault of the USGA and the R&A. My wife is the rules chairman for her women's league this year, and knows the rule book pretty well. So do I. But night after night we discuss some rule question that has come up during her league events, and one or the other of us, or both of us, are stumped for the precise answer. Sometimes we'll be surprised when we consult our well-worn Decisions book and discover the answer was not what either of us thought; and other times we'll be frustrated that we can't find the answer at all.
For such an elegant, beautiful and essentially simple game, golf has created a byzantine and often punitive set of rules that the ruling bodies cannot hope to expect the general public to follow. And disrespect for the rule book leads directly to disregrad for equipment restriction, which in turn leads directly to equipment manufacturers continuing to produce products that challenge USGA and R&A authority.
We all play for different reasons; most of us here, I believe, play for the first seven reasons you listed in your post. But we're not much like the general golfing public, and I believe that if we and our ilk stopped playing golf tomorrow, the equipment manufacturers would hardly notice. There just aren't enough of us, even though our approach to the game is over-represented within and by the USGA.
So, back to your original point -- I completely agree that a unified set of rules is not on the radar screen when it comes to the reasons why most people play golf. There is rampant disrespect and disregard for golf rules -- even within my wife's league, there are players who just don't understand why you can't concede a 1-foot putt in a stroke-play event, and continue to do so -- and this unification of the two ruling bodies won't change that.
The USGA and R&A are out of touch -- not with us, so much, but with just about everybody else. I support their efforts to limit distance; I support the competition ball. I play by the rules, as far as I know and understand them. I just think they're fooling themselves if they think the average golfer cares about the latest decree from The Blazers.