Many of the impure dot coms are branches of much larger companies, where the real cost of shipping and warehousing is being absorbed. Likewise, the companies that have made the most profit off the Internet have been those selling the network components, servers, and server software. They are the ones who make money even when the start-up fails. I suppose it is theoretically possible for Microsoft to halt all of its normal software sales and declare itself an ASP, but I don't think so. Banking is transport of goods, in my opinion.
Fees are paid, responsibility is transferred, etc.
As Adam mentioned, many of the post-IPO wonders are much better bankers than they are businesses. A large and growing exception. What I find bizarre is how easy it has become for public companies to play shell games with their assets and iterate them as IPOs. I don't understand why most of the deals done by CMGI over the past year have been legal, let alone profitable. But I don't understand the stock market in general.