I guess perhaps one could see it ecologically. There should be enough competition that a few individuals don't dictate too much power (over standards etc) that the developer is handicapped but at the same time there isn't too much "polyglot" so that the developer community becomes too fragmented.
I think that's right, but I don't believe we are anywhere near fragmentation. I think the competition that does exist right now among well known languages is healthy. The communities challenge each other, and more times than not the challenge are met. I don't think there's any evidence that things would be better if there were less similar tools. It's not like there's a lack of manpower or strong personalities in any of these communities. I think merging them at gun point, or artificially, would result in benching a lot of great minds.
Only two of those are directly supported by the browser.
No, really. How do you run Ruby or Python in the browser? C#, F#, etc. I might understand if you use Silverlight. Java comes with the JVM. These are both plugins though.
Show me this browser that runs Ruby or Python scripts directly. I want to use it.
Every modern desktop browser supports this. And a good number of small device browsers do as well. Yes I'm clearly talking about virtual machines embedded in browsers. "Browser plugins to facilitate other execution technology have a very bright future. "