Space heating of the national housing and commercial stock has changed fuel source twice in most of our parents life times, solid fuel to town gas and town gas to natural gas.
Switching over to electric is feasible if government and industry decide they want it to happen. Labour published thier plan to carbon neutral by 2030 yesterday which included the roll out of 8m heat pumps which is totally doable if thier is the will.
Probably easier than trying to convert the gas system to hydrogen and stopping it from leaking everywhere. (Hydrogen totally has a place for transport however and industrial heat provided it isn't a fossil fuel byproduct).