The original plans for the 1984 Macintosh was for it to be like a microwave and you don’t upgrade a microwave.
...and, like a microwave, you could get seriously electrocuted (even when the Mac was unplugged) if you tried.
Yet the later G4, G5 towers and the original Mac Pro were among the easiest computers ever to upgrade, complete with tool-free access... so the story isn't that simple.
We're in a slightly odd place at the moment where, because of the performance of the M1 and the late arrival of the M1X, people are looking at low-end M1 machines for applications that would previously have been a job for higher-end MBPs, 5k iMacs etc. Once the M1X machines arrive (presumably with more RAM options) and the M1s go back to being "personal productivity" machines I don't see the M1 starting at 8GB and maxing out at 16GB RAM as being a problem (just learn what that little 'x' does in Safari tabs, folks). I don't have a huge problem in deciding how much RAM I need in advance - it is really down to the pricing (and whether Apple continue to take the Mickey by starting the "pro" machines at 8GB).
I find the fixed SSD slightly harder to swallow since (a) Flash SSD is still a perishable component that can be potentially prematurely aged by software bugs and (b) I feel that SSD prices still have someway to fall in the next few years (assuming chipageddon blows over) so 1TB+ SSDs may become more affordable over the lifetime of the machine. Esp. on laptops where relying on external storage messes up the portability.
