I think TOC's are using COVID as an excuse to downgrade complimentary service in first class. When Virgin took over West Coast, they raised the bar in first class by offering complimentary food and alcohol and therefore East Coast, as it was at the time, felt compelled to do the same. Now Avanti have taken over West Coast, and LNER were at the time still offering complimentary food and alcohol in first class, Avanti felt they had to continue it as passenger expectations had been raised.
When COVID started, both Avanti and LNER very quickly reduced the complimentary first class offer to a collect your own hot drink and biscuits/crisps from the buffet, but no free food or alcohol, with LNER even banning you from bringing your own alcohol on board. Now that Virgin are no longer around on West or East Coast, I suspect Avanti and LNER would both love to ditch the free food, hot meals and alcohol if they felt they could get away with it long term, to the same as what other long distance TOC's offer in first class. Although I note Avanti have now reintroduced the at seat first class offer, they no longer offer complimentary spirits or hot meals, dressing this up as a measure to reduce the COVID risk, and I suspect Avanti and LNER will be watching what each other does very closely to see how much they can get away in the future.
I would like to be proved wrong, but I very much think it is a case of 'it was good while it lasted' in terms of onboard service with Virgin and East Coast in first class, and if this does happen, I think I lot of customers who were willing to pay a premium for the better quality service and superior on board experience will either trade down to standard, feeling the difference in price is no longer worth it, or no longer make the journey by rail at all.
If both companies do decide to downgrade the first class complimentary offer long term, it will be interesting to see what happens to the fare structure and uptake in first class, as the superior on board offer was one of the main reasons Virgin were able to command such premium anytime first class fares on West Coast in the first place.