I work for the NHS (backroom, not frontline, not management though I have managed a team in the past) and strongly believe in its principles but there's no doubt it is going to have to change to survive.
We are going to have to change too. It isn't only patients who are getting older, the staff are too, hence recruitment drives to countries like the Philippines and other locations.
We are all going to have to take more responsibility for what we eat and how we exercise, assuming we have that control and the ability to afford it. There is likely to be a hardening of attitudes towards smoking, drinking alcohol and other harmful behaviours.
Much harder decisions will also need to be taken about what drugs and treatments get funded. It's going to be much more like it was when my parents were young during the depression of the 1930s, with elements of the American system almost certainly.
There are other imminent changes which are long overdue like standardisation of uniforms in England which will save millions once they have been implemented. And AI is going to have to help make more decisions, it's already being used in some areas to great effect.
I wouldn't currently take out private health insurance but I haven't ruled it out in future. Even with private cover, though, or a US style copayer arrangement, there still won't be enough clinical professionals to go round. And what people often forget is that there are no private A and Es so if you're in an accident, say, it's still the NHS who will treat you, at least initially. Private companies can also afford to be very selective about what conditions they treat and you'd better make sure you take that insurance out while you're still young, healthy and cheap to treat.
I would, however, like to see far less politically correct late to the party posturing going on. I don't mind wearing a name and ID badge but I fail to see how having my pronouns on display helps patient care. Unfortunately I currently come under the jurisdiction of a team whose reason for existing is pretty much pronouns and other high profile virtue signalling and it drives me up the wall.