Even if you don’t have the need for spare parts, don’t forget that they deliver security updates longer than any other manufacturer that I’ve heard of. So longevity is not just about the hardware.
EDIT: Also, they just newly stopped selling fairphone 3 spare parts. That’s 7 full years of stocking parts. Not bad IMO. And you can probably still find them in stock at resellers. I see display modules on ebay (from china) and at least one german eshop