It would force compromise on every other aspect of the product.
In the real world = more time (at every stage of the R&D and manufacturing process) + extra material costs (more tooling, more PCBA's, more screws, etc.).
I personally think that this issue will become a very big deal over the next decade or so, but at this point the market isn't applying enough pressure for the big companies to change their GtM processes.
No, but releasing basic board schematics - or even just allowing third-parties to freely redistribute their own custom-made schematics - is. Allowing your supplies to sell board components directly to consumers and third-party repair shops is. Allowing third parties to move used OEM parts across international bounds without fear of having their property seized for being "counterfeit" is.
There is a huge community of independent repair technicians out there who are constantly undermined by the likes of Apple and other major hardware manufacturers. The manufacturers don't even have to "design for repair". They just have to allow repair to be an option in the first place.
Maybe if repair becames a common alternative again, "design for repair" would actually be considered a competitive advantage.
I am sure it isn't, but once upon a time all products were designed for repair.