It seems likely that Coronavirus will be with us for some time. This post considers the situation purely in the UK.
There is promising news from the vaccine trials. But at the same time there is also evidence that the antibodies from a (live) coronavirus infection wear off within a matter of months. This is consistent with the known behaviour of other coronaviruses. (There is also some evidence that some residual immunity remains and a second infection may be less severe).  There is no particular reason to think that any vaccine will produce a more long-lasting immune response than the virus itself, (though apparently this is a theoretical possibility).
There are additional problems with a vaccine. It will be a huge logistical exercise to vaccinate an entire population. It will be an even bigger logistical exercise to do this every 6 months. In reality many people will not take the vaccine. This may be especially so for young people who know they are not really at risk from it (as a rule).
The mortality rate of Covid-19 is not yet known. It is difficult to work out based on the ratio of positive tests to deaths given that the number of positive tests is very much an artefact of the testing policy of any one country. Initial estimates from the UK’s senior health advisers put the true mortality rate at less than 1%.  This is probably higher than the mortality rate for flu. I’ve seen figures of 0.1% to 0.2% for flu. (See  though this paper doesn’t give a source). Coronavirus also seems to be more infectious than flu. One study gives R numbers for flu at less than 2.  It appears that the (relatively?) unchecked R number for Coronavirus is over 2.5.  – So Coronavirus and the disease it causes, Covid-19, is both more deadly and more infectious than flu. A difference between 0.1% mortality and (say) 1% mortality does seem significant. Out of a population sample of 100,000 it is the difference between 100 people dying and 1000 people dying. Out of a population sample of one million it is the difference between 1,000 people dying and 10,000 people dying.
Mortality for Covid-19 is much higher in the elderly and in those with existing conditions. This is the same for flu (though it seems that obesity is an especially dangerous comorbidity for Covid-19). This means (and I’m not doing the maths here) that mortality rates in a sample which excludes the elderly and those with comorbidities will be much lower. It is quite possible that in this sample the mortality rate will approximate to, say, 0.25%. (This figure is a wild guess based simply on the 1% figure from the UK’s Health Authorities together with the knowledge that the disease really does disproportionally affect the elderly and those with comorbidities; nonetheless there are at least grounds for thinking it will be substantially less than 1%). Let’s make the optimistic assumption that the Oxford vaccine does indeed prove effective. That it confers a high level of immunity and, crucially, it works well in older people. There is evidence that this may be the case. 
Taking these factors together one possible end-game scenario for Coronavirus in the UK is as follows; a successful vaccine with a high degree of efficacy will be developed and will be available in large quantities by sometime in the first quarter of 2021. A well-organised programme (one can still hope) by the UK’s Health Authorities will see it given to those most at risk – the elderly and those with identified risk comorbidities. There will be high take-up in this at-risk group. This will be a regular programme with repeat doses available every 6 months. The repeat dosing will work. At this point the crisis is in effect over. There will be no further need for lockdowns. Though people should still be encouraged to practice social distancing, hand-washing etc. The virus will continue to circulate in the wider population and will lead to deaths but now at levels comparable to ordinary flu and therefore manageable. (There seems to be overlap between flu and Covid – see previous post – so this will not be a case for flu deaths + Covid deaths). In time as production ramps up the vaccine will become available for this group and there will be some take up leading over time to a reduction in hospitalisations and deaths in this group.
Over time Coronavirus will take up a position alongside flu as a nasty bug which carries off elderly and already sick people who have not taken up the vaccination offer and which, occasionally, kills someone outside of this group – who has not taken up the vaccine offer. This positive scenario depends entirely on a) a vaccine being designed which does confer a high level of immunity, b) that this vaccine is effective in the elderly and c) that government makes some intelligent decisions about prioritizing the most at-risk in the (free) vaccination programme.
Update: added on news that the Pfizer vaccine based on unverified data (but released early for commercial reasons) is “90%” effective. If this is the likely rate for these types of RNA vaccines there is an additional problem. Does an elderly person with an existing comorbidity who has received the vaccine assume they are protected or do they play it safe and continue to self-isolate? In effect for people in high-risk groups a vaccine with 90% efficacy offers them the chance to play Russian roulette with their lives. (This is just one of several considerations which you will not see reported by the corporate-government sector who are no doubt drooling at the prospect of the billions that will be made from these vaccines).
If a) and b) in the previous paragraph do not come to fruition, or if the scenario is derailed by the virus mutating and causing significant problems for vaccine developers, then the outlook is rather bleak; because it is not possible to lock down an economy indefinitely in this case the end-game would look rather like the “protect the elderly and let it run riot” scenario of the Great Barrington Declaration. A lot depends on the success of the vaccine candidates.