TWBB is the first and only time I ever thought he seemed truly joyless doing press, but I felt it profoundly so. I don't know what was in the water at that time in his life, especially because he seems to reflect on it so fondly now, but I just remember feeling that he was presenting himself as completely closed off, and even feeling like the experience of that production had sapped the light in his eyes slightly. I'm reticent to place too much emphasis on the whole "kids" aspect, which is sensible but also feels vaguely like a catchall. I don't know what it was.
One thing I think is worth pointing out is that his press habits differed wildly between TWBB -> TM -> IV -> PT -- and those were all distributed by different companies. So my money is on the distributors doing most of the bookings and him following those however he's most comfortable. I know there's a tendency to fall into the trap of, "but PTA calls all the shots! He doesn't do ANYTHING he doesn't want to do!" but I would venture to guess that attitude is mostly funneled into posters, trailers, TV spots, rollout patterns, etc.
I remember him speaking positively of his marketing collaboration with the Warner Brothers team for Vice, and I think it's feasible he's relented a bit on micromanaging this sort of thing -- particularly because any distributor he would work with at this point is going to have a good sense of what his vibe is already going into it, and who his films are for.
FWIW, box office receipts on Phantom Thread obviously haven't been stellar (although I would argue better than some here are making it seem -- we forget the film's barely reached international at this point), but it seems to have really invigorated the likes of us. So maybe Focus made a calculation that there's no use in trying to create converts at this point and to just play to the work's strengths -- from a financial perspective a failure (to this point), but from a These-Promotional-Materials-Are-Sick-And-Make-Me-Stoked-For-A-New-PTA perspective, I think it's probably the best of any of his films since Blood.