[tsss]

Heat pumps will never be a viable replacement because they only work efficiently at low heating temperatures. The heat pump itself may cost you 5 to 10k but you may have to spend another 50-100k on insulation of walls, windows, roof, basement as well as floor heating (and thus completely new flooring) in every room to make it work. This is doubly true in the US where many buildings still have single-pane windows (though you have the advantage of not paying 40c/kWh like we peons in Germany).

And btw: heat pumps are loud, so good luck with that high density housing every climate advocate wants so much.