Yep, exactly. That's the reason for upgrade for many. Peace of mind to the guys who has the power to buy from iphone 1 to iphone 999. But in this case, 6 to 6s.
I find it hard to comprehend an upgrade of 6s if its just the ram and proc from an already fast iphone 6. Recent phones are so fast that proc and ram changes hardly matter on succeeding models. (Given that 6S wont shell out any new significant feature) It will be like Note 4's two variants quad core and octa core but is at par with each other. I have the octa core version by regional market. 64 bit vs 32. Did not notice that in real life.
Good example for me coming fromin an apple standpoint when i upgraded 4s to iphone 6 comparison. There is a huuge difference.
However, in an iphone 6 and 6S standpoint, Ram and proc upgrade is not significant in a "future proofing" standpoint for the money conscious buyers. Maybe when compared to iphone 7 it will become significant. But Im very very sure new iOS apps dont get that too heavy for a year-old phone model. Devs has a way for that even if phone is already 3 yr old model. So iphone 6 will run apps well longer for sure based on the current specs. No need to worry for future apps.
Infinity blade runs well on my ancient iphone 4s.
I just hate companies that sways us to buy new that doesnt live up to the actual value buyers are getting as compared to the old.
Bottomline:
If people has the dough, then go.
But if people need to sell their kidney for an iphone, id suggest that they wait til iphone 7.