One of the scientists (Whitty?) said the other day that eventually we will reach a point where the number of deaths is acceptable - much like flu. We vaccinate the vulnerable and accept that some people will still die (because no vaccine is 100% effective) and then we get on with it.
I don’t believe we can make a simple link between that and how far the vaccination programme has got, though, because:
a) the impact of Covid vaccination on transmission is still unknown
b) the duration of immunity from either infection or vaccination is still unknown
c) Covid doesn’t only kill you, it can also give you long Covid, the duration, frequency and effects of which are still unknown.
So, there are too many unknowns (IMO) to commit to a date now. What they could do is publish criteria, e.g. when the hospitalisations are below x we will relax y and so on.
Bear in mind the commitment to vaccinate the top 4 groups by mid February, they contribute 88% of deaths. And the next chunk up to Easter comprise the majority of those hospitalised. It will be starting to look very different (better) by Spring, but not yet back to normal.