First, it tells me that either we as players are getting worse, or that the content is too hard. !
It's a shame you offered this as the two options. lol
What seems more likely to me is that players who would
be doing normal modes in previous expansions are doing LFR instead. LFR doesn't have 'the best' gear but it does generally reward you a ridiculous amount for your effort, has flexible scheduling, and doesn't really depend much on your relationship with 24 (or 9) other people. It's a ridiculously successful feature.
I'm not going to advocate getting rid of it because it'll never happen, but there's a clear lack of incentive to raid to a lot of people. It means we have trouble recruiting and I looked for 6 months before I found a guild that could actually field a 25 man, needed a melee, and
didn't raid 5-9 est monday-thursday.
Actually, most people who say "WoW raiding is easy" are using 3rd party Add-ons or watching videos of other guilds. Go play without add-ons and without watching videos of other's strategies and without your raid leader telling you what to do (and without vent) then return with how "easy" everything is.
Keep in mind that these advantages are available and accessible to everyone, and the game is designed with that in mind.