My parents have the same BT contract line that they have had for 20 years+
It is rarely used for outgoing calls, possibly less than 10 calls every quarter.
Their bill is £45++ / quarter and I would like to do something about it. I am reluctant to cancel the landline contract entirely, it seems to me something of a safety line and I do have no wish to encourage a further withdrawal from the world. But I would like to reduce this expensive overburden.
They do not require internet services.