I agree with the OP that more stroke play courses are needed. But apart from Merion soon, I don't know what plans WGT have this year, and hoping they will surprise us.
I think I saw the number 6 million members - the true number will be somewhat lower but I don't want to get to the stage that I cannot book a tee time on any of the courses!
Currently we have 7 courses and 2 Tru Golf courses( I will ignore the best of courses), which is pretty good considering the quality of the courses. However if you take 2 out (in my case Kiawah because of the shoddy green mapping) and RSG (I dislike this course intensely as I find it so unappealing) I have 5 course and 2 tru golf courses available.
If you take someone who has played 1000 RR they probably have played all courses at least one hundred times, so the monotony does start to set in.. Without regularly introducing new courses players will eventually leave or will certainly play less.
Yes you can take up uneven lies, but not everyone enjoys this. What WGT cannot allow to happen is for the game to become stale, because at that point players will leave in numbers.
This is a great game, but has so much more potential to be even better.