You can still swap between specs in Vanilla, you just need to do some grinding to get the coin for it. Usually given enough time you can get enough farming on certain classes to cover these costs where they may as well not exist in the first place, particularly if you play a Frost Mage and do some Dire Maul AoEing.
It's an arbitrary amount of time invested for something that basically amounts to an additional chore to switch between different variations of what you'd like to play - PvP build, farming build, raiding build, etc.
There's a market for this, and you're not "wrong" for wanting it, but it's silly and short-sighted to believe that you can change the culture and the expectations that Blizzard has only emboldened for the last 10+ years on retail.
2% is also a huge underestimate. We both know that's not going to be where it stops. As it is, Door of Shadows is worth countless damage per second in M+ alone.