In the early 2000’s there were efforts to provide broadband over power lines (BPL). I think one of the biggest obstacles was the radio frequency interference it generated.
Re-reading some of the history of it that does sound like RF interference was more of a concern than data rates. Some places even attempted roll-outs but were stymied by regulators wanting more studies about potential impacts.
https://en.wikipedia.org/wiki/Broadband_over_power_lines
Thanks for correcting me on that.