That's nice of you to say, but I think Smalltalk will probably remain unpopular because it's too different (image-based environment), too powerful (in the Lisp sense, where you can modify core parts of the system while it's running, including the compiler), and worst of all, it's now old, and most developers aren't interested in old tech.
The image-based environment throws me off, but it's being reinvented in a different way: Docker container images.
I'm not really thinking about popularity as a general platform like the way a lot of people use say, Java. I'm thinking about a niche area that is still relatively obscure, will be popular in the future, and very few other technology platform will fit it well.
I think a lot of people will try to throw Javascript as the scripting language for the building VR worlds. It might be workable, but the mindshare for creating VR content is still up for grabs.
The biggest obstacles I think will be in two areas:
(1) An equivalent Github / Open Source thing. Open Source did not really take off until Github and it's sibling clones got popular. That property was written extensively by Stephen O'Grady of Redmonk -- git and Github made things easy to fork and easy to merge, which reduces the friction of having the community contribute things back. I'm not necessarily saying to implement Github for SmallTalk, because that would not bring the uniqueness of SmallTalk in. But for example, I can dip into Github and check out what the Python or Lua community are doing. Montecello baffled me until I realized that you're not supposed to interface it with the web, you're supposed to interface it from inside the SmallTalk environment. This leads to the psychological shadow-side of what makes SmallTalk awesome.
(2) The all-inclusive environment of SmallTalk shares a similar attitude that long-time Lispers have with their environment, particularly Emacs. This is more of a psychological thing. At the minimum, there's likely not as big of a push in creating the tools mentioned in (1). This is the psychological shadow-side of having a very comfortable environment that you can customize to you. There's always going to be some sort of emotional resistance to bringing new stuff in there. Montecello is a great example: the web is kinda the lingua franca of exchanging ideas, so if it's not on there, it's hard to see. I go looking at the Montecello repositories via the web browser, and that experience was broken. It took me a while to realize I was supposed to browse that stuff from inside a SmallTalk environment. (So just off the top of my head: one idea is say, use that Squeak -> Javascript to host an image so you can browse into the SmallTalk world; preset it with Montecello. Just as a starting point.)
I've only looked at the community on the surface, but I'm willing to bet that the Pharo folks are making changes in there.
For me, SmallTalk is a really important technology, not for the world as a whole, but for kids. I usually think of my step-daughter as the yard stick: what would I want to show her about this world? I'm not intending her to make a living off of SmallTalk, but something better, more important: this idea that she can remake her environment by first conceiving and envisioning, and then clearly expressing her intent. That's a skill she can take into any domain.
But yeah something like: run around in a voxel engine like Minecraft, and being able to edit any voxel block in front of you to do something, or even add completely new behaviors. And sharing that with your friends. While using an Oculus Rift. Something along those lines.
