While I havent paid for C4D because the Network I work for paid for it, I did paid for Redshift + XParticles / Cycles, and also for Softimage XSI up until Autodesk cancelled it, and I also have a home copy of R20, courtesy from my employeer. So yes, I too had to decide with the money I already invested about switching apps or not.
Blender Pro? Please be informed about Blender, its source code is free, so the chance it goes to subscription is 0%. You can however right now, grab the source code, make a branch out of it and sell it, but someone else can grab the same source code and give it for free.
_ You are free to use Blender, for any purpose_
_ You are free to distribute Blender_
_ You can study how Blender works and change it_
_ You can distribute changed versions of Blender_
In the last case you have the obligation to also publish the changed source code as GPL.
Last, I was an ex XSI user, so… long term is not up to us, better learn every tool available.