yeah, it used to be that things like Perforce could still exist, because when they were created, they could do things that their OSS equivalents could not.

but since then, so many people have gotten used to the basic model that git offers (even if they still have issues with details of the syntax).

to gain a foothold in this environment is a monumental task, and anything that wasn't unambiguously libre and probably gratis too has little hope.

JJ has a good chance, because it builds on top of git, not replacing it abruptly.

git's replacement won't be there because it was better at being what git is (too entrenched), but because git became redundant as the world changed around it. As agentic development takes over and people stop caring about source code, all the tooling (including languages themselves) and approaches to assist humans will be ripe for replacing with those for machines.