Has anyone read this article?

In an exclusive story, Av Leak claims that Rutan has modified his
spacecraft to improve its stability.

Burt may still make Dec 17th 2003 truely historic with a first private
sub-orbital flight.

http://www.spacefuture.com/journal/j...econd_fli ght

This article raised interesting questions. Why didn't Burt do a
spaceship like this 30 years ago? The only technology that wasn't
there for sure then was the mini-electronics for a super lightweight
guidance control and communication system.

Carbon-fiber snow skis were around in the mid seventies. I don't know
if nitrous oxide HTPB rocket motors were around back then. I don't
know of cruise missile jet engines were available back then.

Can anyone else list some technology or other barriers that made
private sub-orbital flight in the mid seventies impossible or highly
improbable?