Well, two more cents on the pipes, there was a tradition in our family, lost somewhere in the 1940's and 50's, in our case they were apparently too blasted hard to learn for average folk. If one was going to suffer it might as well have been to learn something in vogue like saxaphone.

I agree with Dave, shortage of teachers, venues (and probably craftsmen, skins don't last forever). Fiddles by contrast were stubbornly useful in (and as one-man) dance bands right up til swing killed most community dances. Pipes I think really needed 'sessions' like we have now as a venue to thrive in, and those were very rare in the USA for several decades.

As for the whistle, ya got me hangin', shoulda been the ideal portable instrument. A wild guess is they weren't loud and sustained enough to be the one-man dance band?