Varroa mites are too severe of an issue for an intervention-free, Varroa-free colony to be realistic. In a few decades when Varroa resistant genes and traits become more dominant and widespread, a Varroa-free colony might be possible. At this current time, even with treatments, you are only putting off having mites for the time being. Consistent monitoring is necessary – treatment does not mean you are Varroa-free.
A Varroa-free colony requires several factors to come into play, but the biggest reason a Varroa-free colony is not realistic is, unless you own a massive plot of land, you cannot guarantee what is happening in the hives around you. Feral honeybee colonies and managed colonies will be able to interact with your own colonies. We know feral colonies will not be treated, but there is no way to know what a nearby beekeepers’ treatment regimen is like. Unless your bees live in the middle of hundreds of acres, unfortunately for now, a Varroa-free colony isn’t realistic.
If you monitor frequently enough, employing treatments at the exact right times, you might reach Varroa-free for periods of time. However, for the reasons mentioned prior, in the current state of beekeeping, Varroa-free colonies are only a fleeting moment of time. If we do our part to build strong colonies to be more Varroa resistant, hopefully we can lower the impact Varroa mites have and eventually see their populations dwindle.