So it's been a long while (measured in years) since I bought a ticket. And even then it would have probably been online via a pick-up-at-the-vending-machine. I think the last time I bought a ticket from an actual ticket office was Whiston to Lime Street around 8 or 9 years ago.
Since then of course we've had apps, e-tickets, etc. Of course those of us on this forum who tend to be rail staff or train nerds (myself the latter category) knew about these apps when they came out. Casual rail travellers won't, though. So they'd have still bought paper tickets (either from office of TVM). The impact of Covid is that when people were literally told if they came too close to another person, they'd kill granny, people became aware of mobile tickets and e-tickets. So whilst it was a one-off event that probably drove customer habits to change, it has also brought customer awareness.
And realistically, if you know you can - from the comfort of literally wherever you happen to be at any time of the day or night - check the train times, reserve a seat if necessary, and buy a ticket, then why would you go back to queuing at a ticket line waiting for a piece of paper to be printed out and paying for it over the counter? No evil fascist Tory Brexit conspiracies, just common sense.
[As an aside, I see similar effects in my work as a lawyer. Prior to Covid, from about 2000 onwards, it was possible to have court hearings held by telephone or video calling. Video calling was literally unheard of unless you were a Kazakhstani oligarch arguing over billions (probably because video technology back then meant an actual TV-style video camera and a leased line to the courtroom). Telephone hearings were few and far between and tended to be restricted to 10 minute hearings where everyone was agreed, although occasionally longer or contentious hearings were held. But rarely in the scheme of things. Various multi million £ failed IT schemes were tendered for for video equipment in court rooms which never worked properly and weren't adopted widely.
Come Covid and of course all access to court buildings stopped overnight so by necessity every hearing was by telephone or video. HMCTS (the government organisation which runs the Court Service) relaxed its rules and permitted courts to use off the shelf video conferencing such as Zoom and Microsoft Teams. Amazingly, as soon as there was competition, the expensive in-house system (known as "Cloud Video Platform") suddenly started working properly. Within a few weeks everybody from the court staff to judges to barristers and solicitors got the hang of how to work remotely.
Of course Covid ended and in-person court hearing resumed, but now many courts and judges will conduct hearings by video or telephone whenever its convenient. I've just looked at Liverpool County Court's list for tomorrow and probably half of the cases are remote (not mine unfortunately).
The way of the world is changing, and the only thing Covid did was give a kick up the backside to hurry things along in a path they would probably have taken, eventually, anyway.]