Earlier quoted context omitted.
> would want one when a new one is an order of magnitude better It's not, you're just ignoring two obvious points: 1. a person with no laptop would prefer it 2. a repairable laptop can also have its parts upgraded, so a 20 year laptop could have 1-year old parts
Cheap laptop I've bought in 2011 went through several upgrades: replaced ram doubling amount of GB. Replaced HDD with SSD, added HDD instead of DVD reader. Even replaced CPU to get more cores! Nowadays I can only replace m.2 stick to get more storage. Everything is soldered.
I do agree having back user upgradable ram, disk and GPUs on laptops would be much better alternatives.