You're falling into the trap of blaming individuals.
A casual player logs in 2-3 times a week, and over the years his realm completely dies, it's not his fault so why should he suffer?
No the cost was never "acceptable", it was just a hit you had to take because Blizzard are slow as f*ck and wanted to grind out every penny they could before realising it was causing players to just leave the game.
I was stuck on a dying realm, I couldn't find raid guilds, trade got about 2-3 messages per minute on it, the world was empty.
My choices either were:
-Sit on my dead realm and feel like i'm playing a single player game
-Reroll and leave my character i've been playing for over 7 years and grown attached to
-Quit
-Take the slap in the face and pay the money
I was incredibly close to permanently quitting the game but in the end I begrudgingly paid the money.
Now you can pretend to be Blizzard's financial adviser and say that's great business from Blizzard, but it's a horrible thing to experience as a player. I watched my friends quit, the top guilds move to the couple top realms were you could recruit heavily geared players and places like Goldshire eventually become barren.