Andy Bower (Object-Arts, makers of Dolphin Smalltalk) has some thoughts on being a Smalltalker - here's his summarization of Java:

We started building Dolphin in 1995 and, when Java floated in on the Internet bubble later that year, our disappointment was palpable. It wasn't just that Java was getting very big, very fast and was obviously going to make it harder to sell Dolphin to the masses. It was more that, really, the designers had just missed the point. Or at the very least they had missed an opportunity. Yes, they had a virtual machine and garbage collection, which was more than C++ ever did but what about all that other stuff they could have taken from Smalltalk? What about dynamic typing? What about keyword selectors to aid readability? What about proper Reflection? What about "Everything is an object"? Heck, you couldn't even add two Integers together. It was very sad.

And .NET? Recall that Dolphin is a Windows specific Smalltalk, so .NET was potentially a good thing for them. Except:

With the advent of .NET, I must admit we thought it was all going to change. Here was a virtual machine that was designed to run multiple languages using a common "object" model. Okay, it only ran on Windows but, hey, so does Dolphin so we weren't too unhappy. But where was all that good stuff again? Yes it's all marginally better than it was with Java but, really, writing a performant Smalltalk on top of the current CLR is just impractical.

We saw the same thing here at Cincom. We seriously considered hosting ObjectStudio on top of .NET (and in 2003, Microsoft called me a few times to gauge our interest). The problems are as Andy says - it's just not possible to build a performant Smalltalk on .NET. The JVM is even worse that way. There's reason to be cheerful though:

The great thing from our point of view is that, if you like Ruby you are pretty well sure to like Smalltalk so, hopefully, we're about to get a new influx of dynamic, everything is an object, programmers and that can only be a good thing for Dolphin and for computer science. It's taken 25 years but we're nearly back there.

Yep. After a ten year road to nowhere, the industry might be rediscovering actual progress.