The fact that you claim that there's "zero incentive to do higher difficulties" just proves how ignorant you are on the subject.
Meanwhile, the number of players raiding properly has remained pretty damned stable over the years. And your statement that there's no "locked content behind skill tests" is just pure bullshit. It's called DOWNING BOSSES THAT REQUIRE SKILL AND TEAMWORK, something you simply do not get from LFR. Are you really speaking from a standpoint of experience here? I'm doubting it seeing just how wrong you are...
Unique rewards from Normal+ raids include but are not limited to; Titles, better gear, higher chance at legendaries, rare mounts, 100% mythic mounts, being able to do meta achievements, Ahead of the Curve achievements. The prestige among raiders comes from beating the content whilst it's relevant, which always held true. Not sure wtf you're smoking to believe that this ended with the introduction of LFR, especially considering the fact that we've seen some of the games most unforgiving encounters since its introduction.
It was ALWAYS the case that the vast VAST majority of players didn't play the game beyond solo content, whilst a small percentage felt the will to dedicate themselves to proper raiding. You being blind to that fact because you've got a hardon for hating on LFR doesn't change shit.
- - - Updated - - -
These people ignore facts to support their own agenda.
"Zero incentive" to Shadowpunkz perhaps, which makes him part of the problem. Everyone I know that's a proper raider, still has the need for proper raiding and would sooner quit playing than settle for LFR. LFR simply gives the 99% a chance at seeing watered down versions of raids, and justifes the resources spent on raids as a whole.
Even I would quit if I couldn't raid properly and would be forced to just do LFR, and I'm a no-lifer.