This.
If a new tier raid was released and there were no upgrades people would go spare, a new expansion with new zones, levels and instances comes out and people act like their gear is sacred.

I think you guys are misunderstanding the apprehension people have with the gear transition. It's not that people don't want to replace gear, it's that replacing hard earned (especially if Drop Rates are against you) items with quest rewards from your first quest line really devalues all the work you put into gearing out your character at 80.

If a pair of bracers drops in a level 81 dungeon that replace my 251 Dreamwalker piece, that's fine. That doesn't bother me. But if I replace my swords from 25m Saurfang just because I killed 10 moths the minute I step into Hyjal, that's when I start to wonder what the point of raiding is at all. True, raiding isn't (or shouldn't be) about gear, but I consider the gear a reward for a job well done.

I don't necessarily want to wear my iCC gear all the way to 85 (I like upgrades, they're fun, interesting and give a sense of personal progression), but I don't want to replace it the minute I leave Northrend either.

Also, in before "omg this game is so easy if you don't have hm25icc on farm you should just delete". Not everyone can farm badges endlessly or run ICC 8 times a week. Not everyone has gold pouring out their ears to be decked out in 264 BoEs the minute their alt hits 80. Some people have terrible luck with drop rates and hate the idea of getting rid of gear that they farmed for -months- before it finally dropped. Not everyone wants to look like a hobo in mismatched leveling gear again.