I had the N6P that has 3GB ram so I know you don't need so much ram to have a zippy phone. It's about optimization rather than throwing more memory to compensate for it. For me, I'd prefer to use the money else where since I don't see the urge to push the manufacturer from thinking that more is better.
I'd rather they spend more time optimizing but they won't be able to justify the cost increase without throwing hardware to support it.
You gave a good example of Apple and how well they optimized their OS that's even with 2GB ram, it still runs faster than most phones double or triple the memory. I don't want to pretend I know how Apple code their OS but if you tell Apple their phone need 8GB to cache whatever you throw at it, they will laugh at you point blank and say u need better engineers

Think out of the box and think efficiency. See what google has coming in the next Pixel? Have 6GB or 8GB ram?
I am not going to convince you anymore since you are willing to pay more so more power to you. Just enjoy your phone is what matters most. Cheers!