JJSE,
It isn't just pros, I play that way too (playing for my misses to end up in greenside bunkers instead of greenside rough) I don't have anywhere near the 50% sand saves pros do, but since my recovery rate from rough is worse than theirs too I'm still better from the sand
Weak bunkers lead to a lot of other evils that affect how I play, like taking the risk out of a well bunkered green complex on a driveable par 4 or reachable par 5, not requiring working the ball or being in the "correct" side of the fairway, etc.
It can take a fair amount of the strategy out of the game and allow a sloppier player to match a more skilled player just by virtue of having a deft touch out of the sand. Believe me, I've really frustrated a few guys on courses with well bunkered greens. Its gotta be hard to keep your composure if the guy you are playing against misses every fairway, finds a bunker by every green, and still manages to keep up
Bunkers appear to be no more or less difficult in the US today than they were 50 years ago. But the areas around the greens on many courses are a lot tougher, with rough, mounding, "grass bunkers", etc. Irrigation also tends to create soggy spots that limit your options because you can't be sure how the ball is going to react, so you have to play defensively. Bunkers are easy by comparison, and the more they grow the rough and increase the number and slope of the mounding, the more attractive the bunkers look.
I don't really agree with the "no maintenance" bunkers though, simply because I don't think it is realistic to ever get people to think this is right in our lifetimes. But we could certainly rake with deep furrowed rakes ala Oakmont, use sand that makes the lofted shots we're hitting into the greens these days more likely to bury (while still letting the lower hotter shots of hackers and seniors more likely to still have a playable lie)
I'd really like to see bunkers with one area with a really high lip. Kind of hard to draw, but you see some traps in the UK that are set up such that you have almost no shot (or a high risk shot) trying to play to one half of the green, but the lip going for the other half is pretty low. Do something like that and half the time you end up in that trap you have to make a choice whether to take a chance trying to put the ball close for a one putt, or play it safe for the "guaranteed" two putt bogey.