This article goes a long ways towards explaining what's so cool about Smalltalk, without ever even mentioning it. After talking about the Dorado and the Star (and what differentiated them), this example explains it:
At best I think most people ask "What could people do with this computer". That's a very different question from "What people will people do with this computer"... there are so many nifty features that if people pushed themselves they could use, but have a high enough barrier to entry that people don't bother.
Example: I have a nice thermostat in my apartment. Its fairly well designed and has quick push buttons for "Daytime", "Night" and "Vacation". It was even straightforward to set these to my preferred temperatures for "In the apartment, awake", "Out of the apartment or asleep", and I haven't bothered with the vacation button. Now I have noticed that I don't like to get out of bed in the morning because it is sort of cold. In fact, sometimes I'll lie in bed for 30 minutes because its cold, which is a big waste of time (I'm not very rational when I'm waking up). I have noticed that my thermostat supports scheduling changes between day and night temperature. I even looked at the instructions beneath the faceplate, and it looks like it'd be fairly easy to program. But I haven't done it. The device is usable in the sense that if I wanted to, I could program it, and probably get it right on the first or second try. Its not hard to use. But its a little too inconvenient, because I'd have to special case my weekend schedule, I'd have to set several different times using the fairly slow "up", "down", "next item" interface for setting time (on most alarm clocks etc). The point is, its not hard to figure out, but its stills too much hassle. So while I could program the thermostat, I won't. There's always something that seems better to do with my time, and I can't be bothered (even though rationally I know it'd be better overall if I just program the silly thing).
In a nutshell, that explains the difference between the way Smalltalk or Lisp developers work, and the way C, C++, or Java developers work. It's hard to create tools for the environments that curly bracers work in (excepting Emacs - many people working there write elisp macros to help themselves). Sure, you can create Eclipse plugins - but how many developers actually do it? It's a fair bit of work, and takes effort that most people won't expend (like the thermostat). It's not a matter of can't; it's a matter of won't. Smalltalkers are always making little tweaks and additions to the environment - because the barriers are low. This is one of the reasons I favor image based development - it lowers the barriers for productive twiddling.