For that matter, why haven't I run across these people before? The answer, of course, is _I have_ and I laughed really hard the first time, then promptly forgot the names of the perpetrators. In Ralph Schoenstein's _My Kid's an Honor Student, Your Kid's a Loser_, which I got from BPL before T. was born (aha! This is why I forgot! Well, maybe), there is an uproariously funny profile of the Domans' operation.
Look. It's a bunch of flash cards, either home made, or purchased from the Domans or someone else. You show them to your baby. You convince yourself that this is doing something (like, say, giving your baby Encyclopedic Knowledge). Or whatever. Fairly straightforward. Hard to see _quite_ how the Domans managed to sucker a bunch of people who _should_ have known better (Linus Pauling, Buckminster Fuller) but, to be fair, these are people who have shown a well-developed history of _not_ knowing any better, despite substantial accomplishments in the past within a narrow field.
T. has been largely ignoring the pedalless bike outdoors. I'm a little bummed, but I'm sure I'll get a chance to see it in action some day.