The trick here is the ‘use’ of a new server.
Time-Locked-Progression servers in Everquest 1:
Cost associated? Subscription fee.
Server starts from 1999 original game and continually releases one expansion after another, over a pre-determined period of time. 3 months the next xpac, then maybe 2 months for the next one because it was smaller, then maybe 4 month, or 6 months… depends, they tried a lot of different things.
You were never able to remain in one specific Era.
WoW classic servers:
Cost associated? With the latest news here, you get the option to pick to move on to TBC or choose to remain in the Classic Era and not be moved to TBC, with the cost associated being $15 + sub for keeping your classic era toon while being cloned to TBC, simultaneously. Now you’re paying to keep something you already have, or get denied something everyone already funded when they bought TBC, long ago.
So the difference between the two games and their methods would be the introduction of a new server.
Now I’m just waiting for the buy now to get a 33% discount on clone copy over the next week before the price goes back to $15! Don’t miss out! Get it while you can!