YES they have, in Classic. They restricted both new character creation and paid transfers to a number of realms.
Edit: Found a better thread
Unable to transfer Classic character - Support / Customer Support - World of Warcraft Forums (blizzard.com)
The main thread with the blue post was edited after the transfers and character creations were turned back on. However new character creations and transfers were turned off on MULTIPLE servers for an extended period. This really helped Classic realms stabilize after there were a lot of realm problems.
This is what was needed this time. This may not have been the intention but it was the result. I am not surprised they aren’t doing it considering they seem to just be considered about money, more with TBCC than with Classic.
I agree that the players are selfish. Some of us wanted to move away from the “You are a number” single player with a lobby CRZ, LFR, layering and warmode soulless experience of Retail. That’s why we came to Classic.