Not really. Building a laptop that will last 20 years is several times more expensive than building one that will last 5-10 years. So they will be less accessible to poor people.

They will be less accessible initially to poor people, but if the laptop actually does last 20 years then there will be a lot more on the used market therefore driving down the cost when someone buys a used one. That is the avenue most people who can't afford a new one will likely go.

It makes it more expensive to be on the cutting edge and turning over your laptop once every couple of years, but it makes the used purchases cheaper.

>but it makes the used purchases cheaper.

In fact, no, because they will also become less accessible to the less poor, and less poor will start using them longer and will also buy used ones.