We're having the same issue in the Netherlands, although the grid managers have started replacing them a while ago. They're being replaced with 4G though, which of course also won't be supported forever.

I think a better solution might be to make a local mesh network on the meters, and one base station nearby that has the internet connection.

Most meters are in areas with plenty of others nearby, and there is already a box thing the grid manager owns somewhere near an electricity connection.

People in remote places could just keep using their existing (or new) meters with 4G.

Then the only reason to replace meters will be because the grid manager themselves wants something changed, for network updates you just replace the base stations.