What's not obvious is why this guy thinks that this altered IPOs in any meaningful way. (I'm not even sure why he thinks it altered trading volumes, which is how he claims it affected IPOs.)
But it fits a different pattern, in this article. It turns out that, at least according to this guy, every single change in the capital market structure since, I don't know, 1992 was somehow bad for small IPOs.
Item #3 is "the rise of the internet brokerages." You might think that having a broader customer base would make it easier to sell stuff, but no. Bad for IPOs!
Item #5 is Eliot Spitzer reining in fraudulent "analysis" at various Wall Street firms, which was getting people to invest in stuff they didn't otherwise understand. (Which, in the world I live in, happened to a great extent through internet brokerages, but ... never mind.) It turns out that chasing fraud from the marketplace is Bad for IPOs!
And so forth.
There are some good points here --- Sarbanes-Oxley regulation is a big deal, and so is consolidation on Wall Street. But some of this other stuff really does strike me as a bit of a stretch.