On board service won't get near to back to normal until airlines and governments decide that airlines can operate in a vaguely normal fashion. Talk of 2m spacing between people at all times are balderdash; no airline can operate aircraft like that. Passengers need food on long flights, need to use lavatories, etc. So until that is sorted out in some way (and the evolving consensus is facemasks on board and temperature checks before boarding, possibly combined with profiling previous travel to infectious areas) the service will not improve from "mealtime at a young offender's institution".
When it does improve, my guess is that the hard product elements (seat, bedding, etc) will remain, as will the catering suppliers - because all those are external contracts that can be screwed down on price. On board service may be simplified, to what a smaller, less skilled, and thoroughly demoralised crew can deliver - because they've been screwed down on price too.
Once travel resumes, the economic basis of the countries BA flies to will only be more polarised than before: a smaller number of richer people (and companies) with a larger number of companies and people with little money to spend. The competition for high-value customers will be strong, with a smaller number of them knowing they can command better and better for their (still significant) spending power. Less J/F, but better hard product in that remaining J/F to get the remaining customers.