I don't get what you are suggesting here. Companies build separate phones for separate market segments all the time if it attracts customers. Moreover, there are many companies building phones.

Yet there are ~ 0 caseless phones out there. Your argument does not explain this _at all_. How you can look at this situation and pretend it's not an obvious market failure is beyond me. The only question is what the origin of the market failure is, and whether regulation could help. I don't think for cases regulation is an appropriate tool, for USB and replaceable batteries I think it is, for SD Cards I am not convinced either way.

But to have a meaningful discussion on this, it's first necessary to acknowledge how irrational the phone market actually is, which seems to be something that some people are (ideologically?) opposed to in this thread.