If we ever want computers to be sustainably made - instead of scorching the earth with each new device - we need to stop thinking the way people treat their devices is some natural law of how things will always be.
If this was solved by upgradable components, we would have "solved" e-waste in the 90s.
Component upgradability is not a sustainability solution, because it is architecturally bounded.
Second, sustainability isn’t a true false state. My previous computer, a 2015 macbook air, lasted me until this year. If it had upgradable ram it might have lasted me another 5 years. A computer that lasts forever is probably impossible, but 15 years is better than 10, and 10 is better than 5.