Earlier quoted context omitted.
I think the repairabilty makes it hard to even compare monetary value, since in theory, you'd be keeping the same body, while swapping out the mainboard. Is it cheaper to buy two other laptops compared to one laptop + mainboard? That's what, a 3-5 year timeline? Who knows what prices/capabilities/etc will be like then.
And it isn't just about upgrading for better specs. I'd wager the majority of people's laptop replacement cycle is triggerd by a single part dying (screen, hard disk, keyboard, hinges, PSU), the device being out of warranty, and the store quoting more for the fix than a new device would cost. Being able to purchase the $50 part online and do the repair yourself will probably save the average person thousands over a 3…
I'm curious if you have a different experience where you ditch a laptop after less than 3 years because a single part has broken as you imply.