A large number of economists (in academia, public institutions, and private finance firms), all across the ideological spectrum (Austrians, Keynesians, and every other flavor) did see it happening.

People didn't respond to then, probably because the existence of a bubble isn't a problem, as long as you can delude yourself to thinking you'll be able to time the market so you won't be holding the ball when it pops.

> Instead the economics profession, with a few exceptions like Dean Baker, told the world that things were going just fine.

Baker was far from the only prominent economist pointing to a bubble. In fact, economists were warning about the housing bubble and the fact that it would have to burst before the first dot-com bubble burst (or even expanded) back as far as the mid-1990s. That may actually be the real problem: the warnings had been around for so long no one took them seriously any more; as controversial as identifying a bubble can be, it's a lot easier to identify it than time when it will pop ,and the longer it is pointed to without popping, the more likely people are to convince themselves it's just a permanent feature of the market and not a bubble that will pop.