re1: None of this addresses the lack of dynamic languages on the CLR if Microsoft drops the "Iron" languages.
re2: PowerShell is certainly dynamic (goes beyond type inference and includes dynamic types), though I'll agree that it doesn't use the DLR.
re5: I dispute that the bulk of Ruby users are in the Mac/Linux crowd, and regardless there's numerous reasons why such devs might want to take a dependency on .NET. I won't argue that those reasons aren't corner case reasons, but you've turned this discussion
on it's head in the first place. My point was to dispute the claim you made that by using IronRuby you had to target Windows.
re6: That's not entirely true. OpenSource or not, if Microsoft abandons "Iron" then it's very likely that developers will be reluctant to use them. This is more political than technical, and is unfortunate, and it has little to do with how many people currently
use the languages.