https://www.theverge.com/2016/9/2/12775922/google-project-ar...
I think there is no money in letting people repair and upgrade components.
The problem we face now is that the user can't fix anything at all, repair stores can fix things with great difficulty but they can't get new parts, and apple themselves can't even fix most things because the individual parts can't even be replaced on their own without replacing the whole thing. (The macbook keyboard which was prone to fail was attached with 50 rivets)
All we need is user replaceable batteries, and for service centres to have access to all the parts they need. Lewis rossman can't get access to a chip that was >$1 on the old macbooks and is prone to fail. The newer version of the chip is impossible to source meaning those macbooks either get binned or pay apple for a whole new mobo which costs more than the laptop is worth.
Only functionality missing would be valid cell tower functionality. Wifi and satellite would work just fine
If your ease of repair comes at the cost of quality people will complain about the lack of quality - but nobody specifically wants something that can only be repaired by one market entrant that has full control over the price of repairs.
Also, if you really want to emphasize quality you can run a repair certification program that distributes high priced stickers to aide in people's confidence.
If they could provide the same form factor and make it easily repairable, then I think you would be right that would be attractive to all, however I think small size and repairability are mutually exclusive properties.