Tell me, where's the clear winner between ruby and python? Between python and PHP? Between PHP and Perl? Between OCAML and Haskell? Plenty of languages have managed to rise in popularity through a time when you didn't know if any of your code might run on the future winner. At least with Lisp implementations you know some of your code will work with the winner. "Waiting for a clear winner" is not a reason for Lisp not to grow in popularity.
Perl, PHP, Python, Ruby -- none of these emerged from the womb with a full-grown development environment. They managed to grow to the point where people wrote Eclipse plugins or what have you. Lack of a "mainstream" development environment is not a reason for Lisp not to grow in popularity.
Unless you're implying that each Lisp interpreter is its own language, I don't think your contention really applies. If I learn Lisp on Lispworks, and go sit down at GNU CLisp, I'm not programming in a different language - I'm using a different sub-set thereof. When I sit down to a Ruby program, and then switch to a PHP script - there are fundamental differences between the two languages that transcend the library or features either provides.
Ralphc's point wasn't about there being a clear winner in the dynamic language space, but that each of the languages mentioned had one canonical interpreter.
The issue here is human decisions, not a taxonomy of programming tools. Or do you suggest that Lisp dialects diverge further? If you called them separate languages, would there be a better chance of them growing popular?
On the contrary, I'm suggesting that Lisp dialects do not diverge as far from each other as the various dynamic languages do. That means that the idiosyncrasies each dialect has are going to be more glaring. The other dynamic languages don't (yet) have dialects, so you don't have to take the design decisions of the interpreter into consideration - after you've decided on the language.
In that case, I think that there might be a better chance of a sub-set of Lisp dialects becoming popular if they were described as separate languages. It will be interesting to see how Arc develops from MzScheme, and whether or not it becomes more popular with non-Lispers.
Perl, PHP, Python, and Ruby are all interesting failures. They are important for their effect on languages that will last longer (Lisp, ECMAScript) though.
Edit: I don't mean these are "failures" now, just that they're doomed in the long run. Does anyone think they'll be able to stand any of these languages in 2018? I don't they'll have evolved much by that point either. The older a language gets, the harder it is for it to evolve. And if it tries to make too big a leap, people simply don't go for it (PHP5, Perl 6).
Like it or not, I don't think you can call any of those languages failures. Certainly not PHP, Python, or Ruby. I would venture to guess that all three are more commonly used than Lisp.
Failure in the Grahammian sense of being a dead-end.
"I think that, like species, languages will form evolutionary trees, with dead-ends branching off all over. We can see this happening already. Cobol, for all its sometime popularity, does not seem to have any intellectual descendants. It is an evolutionary dead-end-- a Neanderthal language." - http://www.paulgraham.com/hundred.html
Though I disagree with most of the conclusions in that essay, and in particular the expectation that Lisp (or a direct descendant) is going to be the language of the future, I still think it's way too early to call the above languages failures, even in the "Grahammiam" sense.
Python and Ruby especially are growing in popularity, and I think it's awfully premature to consider them evolutionary dead ends at this stage in the game.
I don't necessarily agree that those languages are dead either. I was just clarifying the point I thought he was trying to make. Plus I wanted to turn pg into an adjective :)
I mean failure like the tyrannosaurus rex. That is, from an an evolutionary perspective. Not at the arbitrary present. And I'd wager that Perl is still actually more used than Python or Ruby, it just doesn't get the love on social news sites and elite blogs.
I think Perl has been relegated to short scripts and legacy code bases. I don't see a lot of new projects being developed in Perl. That's what I meant by leaving it off the list.
Perl, PHP, Python, Ruby -- none of these emerged from the womb with a full-grown development environment. They managed to grow to the point where people wrote Eclipse plugins or what have you. Lack of a "mainstream" development environment is not a reason for Lisp not to grow in popularity.