Is there a definition of “fixable” that people agree on? I had a Dell XPS many years ago where RAM and HDD were socketed to the motherboard, but the build quality was awful and the hinge attaching the screen to the body snapped during normal use. That part wasn’t “fixable”, but I felt like it should have been. I couldn’t have cared less about more memory at that time.

There’s the framework computer, but numerous reviews suggest that thing sucks too, even though it is “very fixable”.

Should all parts for every computer just be available at a big box store or Amazon? What if it became possible to attach more RAM via USB-C, like how the SSD can be expanded via the same? What’s the goal here?

"Fixable" in computer hardware has for many years meant that the computer can be disassembled without having to melt glue and that memory, network card, and disk can be replaced without having to replace the motherboard. GPU and CPU are a bit special. In desktop system I would argue that GPU and CPU must be replaceable separately from the motherboard. In space constrained systems like laptops I can see the need to solder those two to the motherboard so when while not ideal it is tolerable. But disk and memory must be replaceable on their own or the computer is simply not repairable. Replacing a screen, hinges and alike should be possible but I can see that parts may not be as readily available. I have replaced a screen on my HP Zbook and it was just a matter of popping off the bezel, removing 4 screws and unplugging the connector, then doing the same in reverse with the new screen - 15 min job. That is repairable.