This really bugs me. My old Macbook 2011 made it nearly a decade partly by me being able to flip on its back, and replace or update parts at will. It was long a machine in decline, as a mangled third party repair had left it so the back case never quite screwed on right again leaving it structurally a little unstable but in the time I had it I upgraded its HDD to a an SSD, upgraded the ram to either 16 or 32gb (Cant remember, might have just been 16), completely replace the wireless daughterboard with one off a *different model* of mac, replaced a screen after my cat knocked it off the table cracking the screen, and even replace the topcase and motherboard after drunkenly spilling a beer on it. The damn thing was a bonafide ship of theasus, I'm not sure there was a single original part in it by the end. Oh and at least one battery replacement.
Nowdays, you cant replace *anything* in a new macbook. And thats a shame, as this M1 macbook I have is a damn solid machine, and I *ought* be able to expect a good 10 years out of it , but if I break something, or come across a mission critical task that requires more than 16mb ram (Ie, AI), I'm up shit creek without a paddle.