I think you'll find it's more about planned obsolesce... Same with the limited RAM options. Gotta keep people moving on, apparently.I think the gluing of the battery in modern devices is a safety thing, Apple isnt the only one that does it in devices that dont have a typical user replaceable battery. There is always gonna be a slight bit of tolerance in where the battery sits, along with the ribbon cable usually associated with it, you want little stress on it all.
I'm really unsure where to go now. I haven't bought a new Mac since 2012; I have the last cMBP 15".
The reality is that Apple no longer makes the Mac that I need, or at least not at a price that is justifiable. I can see me investing in some new, larger SSDs for my mini and MBP to extend their life for longer, but at the end of that time - then what..?!