I guess it's all a matter of degree, but to me, the Arduino is less like the Altair, which was not very widely distributed compared to similar computers sold in later years, and more like the Apple II-- a great product, widely distributed, but not the first of a kind. I'd say the PIC 16F84 and a Picstart programmer are more like the Altair than the Arduino is.

I do agree, though, that having entry-level boards that are easy to use is a huge step up for the large class of people you mention.