The problem with that is that those bought-in queens will not possess any or all of the many other genetically-derived traits, both active and hidden, which play their part in your bees succeeding in your locality. You are still dependent on breeders outside your area and are not creating a sustainable apiary; admittedly, this enters a whole other area of debate.
The other issue is that once you have the more genetically resilient offspring, by continuing to treat the mites, you are still generating an evolutionary "push" in favour of more virulent strains of mite.