Ally,
Agreed. Again, over 40 years, my typical client was a budget driven course, meaning sub 6,500 SF green, which doesn't leave much room for interior contours. On the courses where I could, I included them like Giant's Ridge Quarry. Also, similar to impossible putts, the better players I know just hate an internal mound, and they admit the reason is a shifting contour between where they strike the putt and the hole is the one that they have the hardest time to control, which is reason enough for some here to include JUST that kind of feature. It doesn't play here in Texas very much, LOL.
And, the supers complain, too. I always give the example of a 0.25 foot high diddle bump (and I assume you are imagining something higher than that) at an 8% slope (for easier mowing). That mound takes an 4 foot diameter circle out of pinnable area, and if you wouldn't put a pin within, say 8 feet of that, the no pin area becomes a 380 sq foot area, or about 6% of a 6,500 SF green. That green, if cups aren't set within 10 feet of the edge, actually starts with just about 3950 SF of cupping area, and that little knob takes away almost 10% of the true cup setting area.
That math is pretty daunting (as I'm sure you know, typed more for others here) to the budget driven course with high play. I mean, is it really that great a feature (when most golfers hate it) to require you to build almost 400 SF more of green at $10 per SF to have that feature? $4,000 for just one green, and over $70,000 if you had to have an average of one of those per green? (That $70K might be only 1-2% of budget, but at least in my projects, squeezing every dime out is pretty typical, and interior contours don't often make the cut, LOL.
Just trying to insert some reality for those who don't play high end clubs as to why their course probably doesn't have a lot of interior contours.
I have no doubt they are great in the right places, but not quite so good on the course that struggles to survive.