Maybe, just maybe, they consider it wasteful to throw away a working machine. The hardware is not exactly green to make, so sure, lets everyone buy a new laptop every year.
You don't throw away MacBooks, you sell them since they are valuable.
But my time has value too, and upgrading from Intel to the new M series did cut compilation times in half for a particular project I was working on. I'm not willing to sacrifice that much time to just keep on using an old machine.
Then there's the problem of reliability. Even if I have a spare MacBook lying around there's a non zero chance my work machine will die at a very inconvenient time (like on site at a customer or when working against a short deadline). After 5 years the bathtub curve starts going up and I don't want to depend on old hardware, even when it's working.
Maybe, just maybe, they consider it wasteful to throw away a working machine. The hardware is not exactly green to make, so sure, lets everyone buy a new laptop every year.