LINQ sucks. Most of those other features have been available in other languages, and in Java we have Groovy, JSR-241. Extension methods == Groovy Categories. Lambda = Groovy Closures (but not as powerful). Query syntax = Groovy GPath/Criteria API/Builders. Duck typing? Check. There are already libraries that provide SQL style abstractions for other datamodels. Groovy is a superset of Java and goes further by providing meta-programming facilities.
Microsoft's approach to language design is interesting to say the least: Kitchen Sink. Java has avoided tossing all of these features in (which routinely are proposed by voted down by the community) because Java developers want to avoid a kitchen sink. About the only future feature I think that will make it into Java is closures (similar to C# lambdas).
Java isn't going to die for precisely the reason that the language is avoiding a rush to featuritis. Although there is a really dumb proposal for Java 7 flowing around to include XML literals integrated into the language just like strings. C++'s language spec was so damn complicated that few vendors could muster a marginally compliant compiler for years.
I prefer a clean and simple language with powerful building block components. Look at Scheme. Deceptively simple, yet still way more powerful and expressive than C# 3.0. C# still has nothing to compare to Scheme's macro facility for example.
