To me, Miff Mole was a great, impeccable stylist of the trombone, who never played a bad note and from 1921 on, consistently showed us what the lowly slush-pump was truly capable of. His style was distinctly different from Higgy, Tea, and Jimmy (whom I also revere).
Why, all of a sudden, did Miff get pushed to the sidelines? Just because the above-named worthies made their splash in the late '20s was no reason for this abrupt neglect.
Lester Young didn't make Coleman Hawkins obsolete. They co-existed rather well for their whole careers. Why did Miff Mole have to get off the Earth?