Jim,
.......you are naturally quite right and we should ignore what the pros do but unfortunately that is not what happens in the real world and is why we rarely see new courses built at sub 5500 yards and frequently see them at 7000 yards plus. In my opinion, it is the cheapest, easiest and quickest way to combat the evils of both slow play as well as spiralling costs.
Jon
A. I think the short course movement is gaining momentum. If not 5500 yards, then max out at 6800, which appeals to the shortest hitting 99.9% of our golfers. I once played with Tom Watson and was 20 yards behind him, if I played with Bubba Watson today, I would be 100 yards behind.
B. I think the cheapest way to deal with it is to nominate the 100-150 or so courses needed for pro tournaments a year, add length or maintain it. And then, pass a regulation (or incentive) that the other 14,900 courses in American just don't use the back tees, take them out of service, stop mowing, etc., which would save money. Adding a new golf ball would just add to cost and confusion.
The whole idea that there needs to be 7K tees because that's what makes a course good, and even when average players want back tees back there, but never actually play them, is the biggest misconception and money waste in golf......
C. And, back on the main topic, just how long would a 100 foot downhill hole have to be lengthened to be a real par 5? Another 140 yards? And, the topo doesn't work for that. Maybe they would have a hole where they open up the front and rear doors of the Eisenhower cabin and require the tee shot to fit through there? LOL