People contributed to the software as it was licensed then, and this software is still available under the open source license and can’t be taken away. Unfortunately that gives no guarantees about future versions or versions that never got made.
I wonder if this will be an example moving forward that people keep in mind when contributing to any OSS project
A 5 year old react would mostly work fine (patch the odd bug if need be). Indeed look at Elm. But terraform is coupled to the moving target of cloud services.
Note I am talking about "keeping up" as a general need for IaC - but it might turn out that the TF fork is a better place to do that in the long term. Time will tell.
I chased TF version updates for a while before being annoyed at having to retool significant parts of my long existing scripts. I gave up and just stuck to a version for what I needed. My only concerns is I may neglect a security update, but this is for personal stuff and not for anything that others use/consume.