Traditional demographics rarely predict Internet use. Given your age, political affiliation, and income, I can figure out which TV channels you watch and whether I should use them to sell you beer or cars. But I can't tell whether you use the Internet and, if you do, whether you'd have any interest in my site. Imagine what the cost of a first-class stamp would be without revenues from direct mail. Without ads, local TV and radio stations would have to scramble their broadcasts and charge monthly subscription fees, the way cable channels do.
Commercial enterprise makes the Internet worthwhile.
Ask anyone who was there in the beginning. When the Web consisted only of sites from universities, the military, and a handful of amateur radio operators, it was merely a curiosity. Surfing the Web didn't become a pastime until businesses took it up as a means to sell and inform. And fast, affordable, residential Internet access will become scarce if companies decide there's no benefit to maintaining a substantial Web presence. Tom, I agree that mass adoption has helped push down costs for Internet connectivity.