Stop talking about bubbles and get back to coding. All the billionaires made in that era didn't pay attention to the idoicy going on around them. They just executed. Now I'm off to follow my own advice.
If a bubble is best defined as irrational exuberance taking valuations as multiples of intrinsic value, then the fact that the exit strategies are different and there are fewer IPO's than 10 years ago is irrelevent. Web 2.0 seems to be clearly Dot Com Bubble 2.0.