Why did Ward Cunningham left Smalltalk and went for Ruby

I found a recent podcast where Ward Cunningham was guest and talks about Wiki, HyperCard, Wikipedia, Wikileaks, Comodore64, RubyForKids and so on.  http://www.pragprog.com/podcasts/show/36 
At 30:30, he begins to talk about Smalltalk how he enjoyed it, and why he decided to go for Ruby.

Personally, I thinks it is makes more sense than Bob Martin's view.

Best Regards