Ruby is still in infancy stages, Python is quite old. Hell Python was the inspiration for Ruby.
I mean look at what is happening in the Javascript space. If Ruby and JRuby implementations get really f-ing fast, we will get some major backings. The problem is that instead of improving Ruby, Twitter decided to ditch it. Maybe they really didn't have the people Google has when it comes to language builders. Since google app engine runs python it is in direct google interest to make it fast. Once it starts running ruby, vuala! So don't worry, they'll get to it.
I'm not sure exactly what you mean by this, but Rails 3 will still be a full stack framework. Something will be chosen for everything by default.
You'll be able to fully switch out ActiveRecord for DataMapper if you wish.
> Hell Python was the inspiration for Ruby.
I've never seen this before, usually I've heard Matz saying that it's Perl. Maybe a typo?
He's also referred to Ruby as "Matz Lisp."
So when does the "enlightenment experience" Eric Raymond promised come ? Or did Matz take it all :-D