The time was right for the Personal Computer revolution in 1977. In 1997, it was the Internet revolution.

In 2007, it was the Social revolution.

There's always opportunity, you just need to find what is now worldchanging, which would be difficult, expensive, or plain impossible before.

It's a bit naive to think that it was ever particularly easy.

I wanted to make two points in response but e1ven has made one already - that visionaries in another time would probably just have created something different. That restlessness and urge would still exist, they'd likely just react to the different environment.

Secondly, even in hardware, there are opportunities like Kickstarter where anyone bold with a well-presented or confident idea can get some backing. There's a bottle-opening-iPhone-case on there (something that might be presented as a sketch on a comedy show and ridiculed) with $20-30k behind it! I was hoping that was a joke.