Discrete replaceable components use up more space, which leaves less space for battery. On top of that, Apple are most likely getting power consumption and performance benefits from integrating the SSD controller and reducing the length of the traces to the RAM chips by an order of magnitude (https://news.ycombinator.com/item?id=25258797). Take a look at the logic board for an M1 MacBook Air: https://photos5.appleinsider.com/gallery/38927-74332-MBA-Tea... There's just no room for RAM sticks and and M2 slot. You could make a different laptop with those features, but it's a laptop that from the point of view of most consumers would be worse.

>but it's a laptop that from the point of view of most consumers would be worse

"Worse", but the insignificantly "better" one is landfill in a few years time when the battery/storage/keyboard/anything has a fault, or even just when it needs more RAM or storage.

Most consumers are just ignorant.

Do you have any stats on this? I'd be surprised if Apple laptops ended up in landfill quicker than their competitors' on average, given the huge second hand market. You also have to bear in mind that the vast majority of 'broken' laptops just get thrown away or put in a cupboard, regardless of whether it would be theoretically possible to repair them.