So they still have another three years to go before they make average and then perhaps another six to nine years after that to make up for the ones that failed or were discarded early. Sorry but I do not believe the average life of a laptop is twelve years because there would have to be many 18 to 20 years-old laptops still in use. I have several Dell Latitude D620 still in my "family fleet" and they are ancient by any way you look at it. They are still running Win XP SP3 and I am probably in the very few that are still using this model. If I go to any forum, including this one, and mention the model I am told to dump it before I do anything else. And this is a computer that is a bit over 12 years old. Twelve laptop years are like 96 human years. It may be the upper bound of life expectancy but not the average.
In any case, it is irrelevant to the point of power consumption being lower in laptops. It is not. There is no magic "lower consumption chip" on a laptop. Laptops use less power because to save power they are designed to have less processing power which means lower consumption, that is all. It is not magic. You can just get an older desktop with the same processing power as the laptop and it will cost you less.
Laptops cost more to purchase and to maintain. There is no way around it. If you need the mobility then you pay extra for that convenience but if you do not need the mobility you are paying for something you do not need.
I have directed family members to do cleaning and minor repairs on desktops which they could never do on a laptop. Just last week I directed by videoconference my wife's sister to clean the processor heat-sink and fan of her desktop. There is no way I would have even attempted to do it with a laptop. When we bought the desktops at the beginning of the pandemic I instructed her on how to replace memory modules. Again, no way I would have suggested she do it on a laptop.
Back when I got my Dell D620 the NVidia video chip failed and the cost of the repair made it not worth it. Simple as that. (Many failed and there was a class action.) A relatively young laptop bricked and not worth repairing. Luckily, in one of my trips to China I had it repaired for only a fraction of what it would have cost me at home. It is still going strong. If it had been a desktop replacing the video card would be trivial but with a laptop it did not make sense to pay for it.
I run into this situation often. "Hey, I have a 5~6 year old laptop and X does not work, what do you suggest?" And I suggest they get used to having a laptop where X does not work or they buy a new one.
Laptops have one thing going for them and that is portability but in every other respect they come in behind. They are more expensive to buy and repair, less powerful, less flexible to upgrade and maintain, etc.
On a desktop I can connect a nice 25" monitor and not have to be stuck with the smaller laptop screen.
Again, for me what has always worked best is to have a more powerful and up to date desktop and a much older laptop for travel and backup. It is a good combination that has served me well and I would recommend.