You're a little late with this topic. About 18,000 surfers responded to a poll on Ampland (
http://www.ampland.com/poll/vote2.php?poll=31) recently and only about 20% replied that they were still on dialup.
Even if these results are skewed for some reason, there are certainly more broadband users around than 2 or 3 years ago. Yet apart from the addition of bangbros/TGP-style front ends, paysite design has barely changed in longer than that.
The speed issue is one of several in this business that have an appealing logic that isn't really born out by experience. Nor are paysites the only ones to prove it is at best a simplification. Some of the most popular TGPs run at over 150K. In fact before its recent redesign, Easypic was more than double that size.
If you were to point out that 2,000+ paysites between them have only two basic design styles (graphic or TGP), I would agree about the lack of imagination this represents. If you were to write that many are fairly competent photoshop jobs, but have little to do with selling, I would agree with that too.
I even agree with your basic premise to the extent that if whatever you are making the surfer wait for doesn't make the wait worthwhile, then it is self-destructive. And there are people out there with whom a non-/less-graphical approach would be more effective.
But I don't believe the bandwidth issue is the main one any more. Rather it is the way that all the sites tend to blur together after the first few. In respect of our approach to sales pages, it is remarkable how such a new industry, one that we often claim represents the leading edge on the 'Net, so quickly settled into a rut.
BTW (and slightly off topic) isn't it a sad comment - although about who? - that many sponsors seem to feel that the real heavyweight graphics and flash stuff is needed in their webmaster areas?