I'm not really sure what you are claiming here. My experiences with Smalltalk ended 20 years ago with IBM Smalltalk and Digitalk Smalltalk/V. At that time, they both used the host operating system (Windows or OS/2) for UI widgets, windows, and such, and any applications you built in it could be packaged up to be launched as any other application. One could use such an application and have no particular sense of isolation beyond an application written in a more mainstream language (like C or C++). Have modern Smalltalks regressed in this regard?
The images on the current website look very similar, so I don't it's changed much in this regard. This has been my typical experience with Smalltalk languages, with the exception of GNU Smalltalk whose specific goal is to integrate with POSIX instead of creating a walled garden.
Do you want to perhaps point to a specific time in that video, and compare it to a non-Smalltalk environment in a way that makes this purported isolation apparent, because I don't see what you mean.
I don't recognize whatever operating system the demo was done on, so if the Pharo system is not using native widgets I would not know, you'll have to explicitly state if this is the case.
The presenter is in the host operating system (Mac OSX) until the Pharo image is "up and running" at the 0:40 mark. Everything until the presenter opens up debian at 5:00 is custom Pharo based desktop / window management / even the mouse cursor if you look closely.
Then this just means that Pharo is one of the Smalltalks that does its own window management. I think Squeak might be the same. It is not a general characteristic of Smalltalks though, and certainly is not part of their essential nature. As I said, IBM Smalltalk used native widgets and windows, and had good interaction with the rest of the operating system.
I don't think you can draw a general conclusion about Smalltalk from a specific example, especially like this one.
