There's one thing new laptops have which old laptops don't:
Warranty.
If you depend on your laptop for work, and one day it suddenly stops working, with the manufacturer's warranty (assuming you checked the correct boxes when buying the laptop) you can have a technician with spare parts the next day fixing it, and it'll be as good as new (and unless it was the storage device which failed, you won't even need to reinstall anything). After the warranty expires, things are more dicey; you might or might not find spare parts (assuming you know which spare part you need; a technician can come with several sets and take back the ones which weren't needed), if you do they might take some time to arrive, and if you don't, you have to buy a new laptop on a short notice (which might also take some time to arrive).
Unfortunately, the longest laptop extended warranty I've seen so far is only 5 years. Which means that, after 5 years of use, it becomes riskier to rely on it. It also means that the manufacturer expects it to work fine for 5 years (otherwise, they'd lose too much money on the technicians and spare parts), but not much longer than that.
Warranty is like the extended warranty on cars. Largely you are overpaying for it and not gonna use it. Vendors use scare tactics to force consumers to keep overpaying for warranty (what if it breaks?), just like car stealerships do.
Meanwhile there is pretty significant chunk of people live just fine with laptop outside warranty. I have never ever used warranty on any of my laptops. If anything breaks - I just go to my nearest indie laptop repair shop, or just fix it myself (watch youtube video and order spare parts on ebay)
Lenovo and Toshiba screwed me over on a warranty. I had a power brick on another laptop die the day after it went out of warranty, only to find the replacement was > $100 (in the early 2000's).
I've heard other PC manufacturers are similarly bad. Do you know of any with a < 48 hour turn around time and a > 95% repair success rate?
Warranty.
If you depend on your laptop for work, and one day it suddenly stops working, with the manufacturer's warranty (assuming you checked the correct boxes when buying the laptop) you can have a technician with spare parts the next day fixing it, and it'll be as good as new (and unless it was the storage device which failed, you won't even need to reinstall anything). After the warranty expires, things are more dicey; you might or might not find spare parts (assuming you know which spare part you need; a technician can come with several sets and take back the ones which weren't needed), if you do they might take some time to arrive, and if you don't, you have to buy a new laptop on a short notice (which might also take some time to arrive).
Unfortunately, the longest laptop extended warranty I've seen so far is only 5 years. Which means that, after 5 years of use, it becomes riskier to rely on it. It also means that the manufacturer expects it to work fine for 5 years (otherwise, they'd lose too much money on the technicians and spare parts), but not much longer than that.