[carpal]

There are two main differences:

1) Apple was a hardware startup. Hardware startups need funding and someone to aggressively sell the product in person to big vendors. Software startups don't usually need that kind of person (unless they're going after the Enterprise cookie).

2) It was in the 70's, and startups were, in general, harder to start than they are now.

[carpal]

I went a bit more in-depth here:

http://subwindow.com/articles/12

It turns out that Apple is a totally perfect example.