I think a bunch of this is off. Single mode fiber is cheap, it’s been around for a long time, and as far as I know, even old single mode fiber supports modern

I think a bunch of this is off. Single mode fiber is cheap, it’s been around for a long time, and as far as I know, even old single mode fiber supports modern standards just fine. (There have been improvements in tolerance to bending and in performance at extreme bandwidths far, far in excess of anything in your house.) Single mode fiber transceivers are now cheap and use less power than 10GigE copper, but until recently they were expensive. Multimode fiber comes in OM1, OM2, OM3, OM4, and OM5, and the older variants don’t get amazing speeds by modern standards. Copper takes quite a bit of power at faster speeds.