The extra profit from pre-emptive upgrades is probably cancelled out by the increased cost of warranty repairs. Repairs get more complicated, more costly, and more consumers end up having their devices swapped out where previously individual parts could have been replaced.

I think it's more so a side-effect of the relentless push for smaller, thinner devices.

That aligns with the priorities of most consumers. The average consumer is not going to upgrade their hardware — at least, not themselves — but they do want a sleek, slim design.