Regardless of the merits or lack thereof of changing the license, it'd probably present an even larger problem, since they don't seem to ask for copyright assignment and they have 100+ contributors, all of whom would have to consent to the new license or have their code thrown out and cleanly reimplemented.
Agreed here. It's tedious to change license later on. So that's why there's tools to push it along, it's not the first time [1]
As a stop gap - they can implement a contributor clause starting immediately. They can also say future commits post-[ref] are <this license> until the prior code is sunsetted.
Typically there is an uppercrust where a very high percentage of the contributions lay. I haven't looked at the code (played the game all the time back in HS) but I'd bet you 90% of the code contributions are with the top 5 committers.
