Second, because this is primarily due to economies of scale and predatory behavior from economic giants: if consumer/environmental protections don't outlaw ethical abuses from the few corporations who capture the market (see also planned obsolescence [1]), the "ethical" alternatives are always going to be more expensive and less attractive.
Third, because there are simple ways to have a strong impact immediately. For example, by forcing all hardware manufacturers to publish the entirety of their data sheets / schematics / research, you'd find a much better OS support for older devices (and new devices too), which would bring a practical incentive (cost) to use older hardware which currently has to be thrown away (for example if the OS does not support newer TLS standards [2]).
The situation is only bad because we let it be. Going with big tech for short-sighted, individualized gains, fails to address the elephant in the room that we as humanity can do so much better and everyone would be better off.
[0] https://en.wikipedia.org/wiki/Wirth%27s_law
[1] https://en.wikipedia.org/wiki/Planned_obsolescence
[2] https://f-droid.org/pt/2020/05/29/android-updates-and-tls-co...