Hard disagree. First of all, it’s true that upgrades were not a solution to sustainability in the 90s, but the issue was that computers were gaining ground exponentially. In just a few years, everything you had was so outmoded it was hard to imagine hardware that lasted more than maybe 5 years. That has changed.
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.