

You don’t need bandwidth to switch streaming services and import your old playlists though. For example a streaming service like Tidal tags all AI music and does not monetize AI generated music.
And if you weant the music straight on your phone, something like Opus 128 kbps is already considered high quality (we have come a long way since mp3). Let’s say your cousin has 20 000 songs. That’s about 60 GB in that form, which fits on most mid grade/flagship phones.
Stone or concrete walls are normal in many countries.
You can indeed use a hammer drill to drill holes. You can buy them for as little as 30 dollars these days. And you can use an angle grinder to make cutouts for cables/tubes, and apply plaster afterwards.
Many houses in the colder regions already have cavity walls with insulation in between the walls regardless of the building method, so I don’t think this method is very wasteful in amount of material.
However, I agree that 3D printing houses had various downsides, such as the weird surface, inflexibility to modify/expand/repair after the initial build and potentiality worse insulation characteristics. I am more of a believer in prefabricated houses, where building houses becomes an industry instead of a project.