Going back to the OP I think the problem is created by Someone posting a question with too little information...
e.g. "I like shooting motorsport. What's the best lens for the job?" - and yes the answers will come back a 70-300 f2.8L etc etc.........
whereas if the question was. "I like shooting motorsport, what's the best lens I could get for this whilst keeping it under £500" - you'll probably get some decent answersa nd things wouldn't escalate.
Interesting debate on the pro bodies and having never held one probably not the best to comment....... but, hey ho, I'm going to.........
Surely it has to be horses for courses. Yes a sports togger will probably want/need insane ISO and a long fast lens and s/he can have that now thanks to the latest offerings but there were plenty of decent images prior to the latest pro bodies.......(interesting comments above about f2.8, separate the background etc, and i am sure that catches the picture editors eye, which if you are a pro is what it all matters about, however I wonder how many of the paper's readers will look at that and comment about the aesthetics of it?)
My perception is it used to be a megapixels war, because we all
know that 14 MP is infinitely better than 12MP - in fact anything less than 12MP just bin it


and I am guessing cramming more and more pixels into the sensor without the price of the sensor going stupidly silly was getting to the laws of diminishing returns, so the new big thing is ISO and HD recording....:shrug: If the big players cannot advertise and market new goodies and gimmicks then people won't buy them etc etc..........
Then I look at something such as a 1D Mk IV...... £3650 on a well known website.(and for that price you don't even get full auto mode

- it's a rip off I tell you!!) ....... If I were a pro would it be worth be chopping and changing its predecessor for one? Probably not, as my perception is that whilst the latter one is possibly marginally better with its new functions the old one didn't have, is it worth the £2k (?) outlay for these small benefits? Or from a non pro point of view the 50d is £665 so is the ID IV 5.5 x better????
However the difference between a pro body of say 10 years ago and today is huge....... and pretty much your average consumer DSLR will outperform the older original pro digital bodies......... obviously the advancements model to model back then were much greater and more significant than they are today......