Host parasite relationships can end in one of only three ways: extinction for either or in a balance between the two. The most likely outcome is surely to find a balance.
Varroa Destructor is an introduced pest to the Western Honey Bee (Apis Mellifera). The bee does not have strongly expressed resistance to mite. The most advantageous position for the mite is to be in balance with its host. Varroa rely entirely on the Honey Bee for their complete lifecycle. There's no point in exterminating yourself by killing your host. When will that resistance emerge? There are reports that it is starting around Oxfordshire already.
Honey Bee resistance could emerge through hygienic behaviours include grooming or removal of infected brood, or through immunity to the diseases which the mite carries and exacerbates. I don't know of any other ways, but there may be more.
In Swindon, a local beekeeper reports that his bees are ejecting infected brood and biting mites. None of my hives have collapsed, despite strongly expressed Varoosis diseases early in the season (DWV and at least one of the paralysing viruses). Evidence of those diseases stopped after May this year. Mite fall in Hive A had been alarmingly high. The fall of mites was much lower over summer, but that's probably due to them being within brood. It will be interesting to see whether mite fall rises into the Autumn.
I will comment on my own hives and pass on any credible reports of resistance in my area.