The old version stayed around but (essentially) nobody wanted to use it. If they had, the forked version would be worthless. That is the difference. A cryptocurrency fork cannot succeed without the consent of the community. No one is compelled to use it the way that you are compelled to accept the decisions of a regulator.

Well, the consent of some of the community.

Potentially far, far less than a majority of the community, even, considering it's not one person, one vote.