I agree to your points related to lazy programmers and inefficiency. But this movement cannot be held up but will be even supported if hardware resources are extended accordingly with each model iteration. Such things were better in the 8/16 bit computer era.
There are phones out there keeping 8GB of ram. Many conventional computers out there don´t even keep that much (even my old rag still runs well with only 2GB non-swapping).
But how much actually is sufficient? Gamers never have enough, but this market is recourse hungry anyway, so not to be combined with anything called “fair” or environmentally friendly.
For every day usage 2-3GB should fully suffice imho. I keep about 80 apps installed. I once started as many as I could but never met troubles running out of memory. And the phone kept its performance. Although these devices more and more turn into complex pocket computers still they are phones. As long as I cannot use it to the fullest extend like normal computers with multi-display etc. everything is limited to only 1 active task and the rest is based on simple task/screen switching.
I am not quite sure how the Android memory management works in detail as there is no swap memory option available as Linux and other OSs offer for conventional computers. So my guess is too that there must be a lot of memory shifting going on in the background.
Up to now I also never have heard of someone replacing his phone because permanently running out of system memory, but maybe of storage as apps also grow and having a sd card slot for memory extension is not a standard and probably will stay a limited option because whoever wants to force the usage of cloud services to make even more money with user data.