The railway needs the crowds back in due course, for the sake of viability, but you raise an interesting point.
The mask debate has created a lot of heat, but one of the other Covid mitigants on the railway has been to ‘space out’ passengers by means of reservations; suspending the lower tiers of Advance fares, or self-policing by which those travelling short distances stand in the aisle rather than sit next to a stranger who has, in any case, ‘reserved’ the seat beside them with a bag. And because passenger numbers have been depleted by the lack of commuters, the policy of creating personal space for those who are travelling has worked reasonably well, although there has still been some crowding here and there.
Now, there are plenty of advocates for the end of the mask mandate, but the current popular policy of (virtually) guaranteeing a ‘2’ to oneself on a London-Edinburgh or Devon-Newcastle run will also have to end.
When the long distance TOCs come out and say ‘okay, it’s a seating free-for-all again, sort yourselves out and be prepared to share with a stranger as the new (old) normal’, from which quarters is their support going to come from? Having a ‘2’ for sole occupancy is a Covid restriction just as a mask is, but I’ve not heard any complaints about it!