The intention of tbc was for people to progress from Kara to T5 to T6, exc. The phases don’t change that experience.
Paid boosts had a tbc version called recruit a friend. You just didn’t have to pay for it. And it was far better at leveling multiple toons than what the 1 boost does.
Store mount was in tbc in the forum of the card games it’s you could get. It was the physical form of the cash shop.
The other things are not something of the games design, but of player behavior and RL changes, there is no way for blizzard to control that. If you want to relive that part of your life then go by a lot of hot pockets and sprite, lock yourself in your moms basement and play from there. That’s your choice to recreate that part of your life.
The goal is to recreate tbc experience as best as they can, which involves respecting the origional games design goal intentions. Some changes have been made, but that is never a justification for more changes. Unless you want to admit the slippery slope isn’t a fallacy, because once you use past changes as your justification for more changes, then you are on the slippery slope.