It's just the Yanks that have subsidised natural gas in many states, and a messed up energy infrastructure that gives electricity prices in the same range as what we have in Europe while being at war.
Seems like its still pretty low in Europe outside some northern countries. Germany is less than 2000/100000 people.
https://www.theecoexperts.co.uk/heat-pumps/top-countries
Meanwhile this link says US has a 15% adoption rate across all income groups. That seems higher than I expected.
https://energypost.eu/u-s-heat-pump-adoption-is-evenly-sprea...
Is there a better source on heat pump adoption rate in Europe and US?