[...] When is it going to pop and who is going to be left holding these bags?
That's some serious lack of self-awareness, right there. All of the arguments can be, and have been applied to btc earlier as well. I didn't believe them back then, and as time progresses, that position is only confirmed. That said, nothing per se means that a bubbling alt market is a tulip mania, just like the bubbling btc market wasn't in itself a necessary signal for tulip mania back then.
Oh, it was. And it took almost two years to start recovering.