Why Smalltalk is the productivity king

I've been thinking about why I'm so much more productive in Smalltalk than any other language. The reason is because I'm curious if you could bring some of it to other languages. So, what makes Smalltalk so special?

• Incremental compilation. There is no cognitive drift. Compilation happens at the method level when one saves the code. It's automatically linked in and can be executed. Smalltalkers enjoy programming in the debugger and changing code in a running program. The concept of having to restart an entire application is foreign to a Smalltalker. The application is always alive and running. In other languages, you code while the application is not running. Programming a live application is an amazing experience. I'm shocked that it's hard to find a language that supports it. Java running the OSGi framework is the only example I can think of. But, one still has to compile a bundle (which is larger than a method).
• Stored application state. Smalltalkers call it the image. At any point in time, you can save the entire state of the application even with a debugger open. I've saved my image at the end of the day so that I could be at that exact moment the next morning. I've also used it to share a problem that I'm having with another developer so they can see the exact state. It takes less than a second to bring up an image. It has the current running state and compiled code. One never spends time waiting for compiles or applications to start up.
• Self contained. All of the source code is accessible inside the image. One can change any of it at any time. Every tool is written in Smalltalk. If one doesn't like how something works, one can change it. If one wants to add a feature, one is empowered to. Since everything is open, one can even change how the language works. It's programming without constraints. The original refactoring tools were written in Smalltalk.
• Freedom from files. Allows Smalltalk to store the code in its own database. The shackles of the file system makes compilation and version control trickier. Smalltalk can incrementally index code to make searches quick and efficient. The structure of the code is not forced to fit into the file system mold.

Now, the question one has to ask is why don't we have these features in languages that we use now? Personally, I would love to be able to keep my application running and change the code as it runs. I just want to end productivity lost to application restarts and compilations.