This is all about tradeoffs. There are benefits to soldered in RAM that may or may not matter to you. Have you never had to reseat RAM after you moved a machine around? It also allows better tuning/binning of parts (making sure that timing matches). I remember a talk at WWDC about this years ago (back when the whole conference was technically covered by an NDA). I do not know if any of it ever made it online.Not sure why there are customers that defend this practice?
I have no numbers so I cannot speak to the value of the tradeoffs. I know that I had to replace the 3rd party RAM on a few of my older minis, but none of my minis with non-replaceable RAM have failed. Again, anecdotal evidence (so I would not even depend on it myself), but I do remember someone saying that one of the most common laptop problems was RAM sockets failing.
I do not claim to know all the reasons for every decision Apple makes, but I also do not accept the view that every decision is just to maximize profit. To me, this is the same as many other decisions about which people on here complain. I look at the total package and consider based on it.
Just as some people wish iOS/iPadOS/tvOS/watchOS were completely open, and that all Apple hardware had user replaceable/upgradable storage, RAM and CPUs, I am comfortable with the tradeoffs in functionality, pricing, reliability, and stability that Apple has made.
All things being equal, I would rather have these machines cost less and let me add/replace/upgrade everything. However, I also realize that all things are not equal and that forcing those decisions would create changes I might or might not like. Since I cannot know, I make my decisions on what exists. I am comfortable with the choices Apple has given me.
You clearly are not, and have every right to leave the ecosystem. I just wish that those who share your view would acknowledge that there might be other reasons for the choice that were made other than "greed".