In terms of future-proofing I mean the 17 base should get at least 5-6years of iOS updates if not more.
The 12GB of RAM in the Pro models is likely for some Camera features along with future Apple Intelligence stuff.
The 11 Pro Max with 4GB RAM got iOS 26, that is now a 6 year old iPhone.
I get the feeling Apple will stick to 12GB RAM for a few years to come, I would be surprised if we see 16GB RAM before the 2028 Pro iPhones.
My 15 Pro Max has 8GB RAM while my 17 Pro Max has 12GB RAM, both keep apps for a pretty long time in RAM (unless the app is developed to immediately cache when I leave it), so I am not seeing a big difference there.