-30, -40, why care? It's just a number.
As equipment is changed, courses will play to lower scores. Pro scores relative to par have no meaning to the average recreational golfer. Scores today can in no way be compared to scores posted by pros in the past. It is a different game.
Changing courses to "protect" par is a wasteful and losing endeavor. Even when it is done, recreational golfers never play the same course setup and would not enjoy it if they did.
Rollback makes an interesting discussion, but it will never happen. Equipment manufacturers will never allow it, and money rules. More gimmicks & gadgets will come along and change the game even more. We already have adjustable clubs, range finders (now with elevation factoring), smart phone based swing analyzers, hotter balls and clubs. If there is a dollar to be made, more will follow. The horse is out of the barn.
Amateur competition is really the only place that this matters and that is a small part of the game. On the high end, pro golf is entertainment. On the low end, the 98% of golfers who are simply recreational players are largely unaffected by rules and equipment and serve only as a market for the dreams being sold by equipment sellers.