Is spot treatment of Drywood Termites (airborne) ineffective?
The only real solution is to kill the colony and ring the whole house with slow-acting termiticide, like fipronil. Spot treatment is a start, but only if using long-acting poison and when followed up with a whole-house perimeter treatment, including the area where they got in. Not much help only treating the perimeter if they came in under the bathtub.

Or, you can tear down the building and rebuild it with masonry walls and a metal roof structure and plaster instead of paper-faced drywall, and then termites become your friends, turning dead wood on the property into healthy soil you can grow your food in. What a colossal shame that we make buildings out of termite food in parts of the country with aggressive and omnipresent termites.