You only care about trueness if you're riding the bike, and you ride the bike with tires on and inflated, so what's wrong with truing with tires mounted and inflated? Assuming your truing stand and dishing tool will accomodate this. Obviously easier for lateral than for radial truing.

Even when I true a wheel with tires off, I will recheck true after mounting and inflating the tire.

Should road wheels never need retruing?. In the real world, you do hit potholes and pavement lips, so I find that even good wheels do go slightly out of true over time. I mean by 1-2 mm. If that doesn't matter, then I guess no retruing is needed.