Interesting on Crash & Repair Salty being found in the USA. Someone a while back said they thought that was an Australian exclusive!
This is a late reply, but I'll take a stab at it. Yes of course the sets have been dumbed down, but I should think the reason is obvious. Mattel is pretty clearly aiming trackmaster sets at ages 4-6 (maybe up to 8) with NO attempt to encourage older or younger kids to play with them.
They've shunted younger kids into the take-n-play stuff and (AFAIK) removed the ability of the trackmaster trains to free-wheel in "off" position.
Since the line is only compatible with it'self now and there is no Fisher Price version of the "real-world" Tomica stuff, there is no incentive to keep any real-world functionality. The key is this:
All Fisher price wants to do is keep kids attention for as long as they are interested in Thomas and Friends, and that really isn't going to be past age 7 for most kids.
My son just turned 5 and I can already see him playing less and less with the Thomas characters and more and more with the few Japanese Tomy Trains we've been able to acquire. I doubt he'll be interested in Thomas by the time he's 8.
Of course we all know that our 3-6 year olds are more than capable of putting together creative layouts with track rather than just playing with playsets, but a colorful playset sure looks tempting to a kids (or a parent) on the toy store shelves.