I have spent a few evenings playing with early releases. I like the ‘turtles all the way down’ idea, but I am waiting to see more mature releases. I have spent much more time with TensirFlowJS that works well, has many great examples.

From what I understand this is mostly because they hired the Swift guy.

I understand the benefits compared to Python (although I would have preferred Go or Kotlin). But what happens when the guy eventually moves on in a year or two?

Google's making a big investment in Swift, so if Chris left and they were interested in continuing to support it they shouldn't have a problem.

I've gone to Swift on the Server conferences hosted/sponsored by Google, their (non-TF) Swift teams are building some cool Swift tools, etc.

This is incorrect; swift is open source and has linux deployments : https://swift.org/download/

Linux support is still WIP. Some parts are missing

Google is not at all a Go shop. Google is a C++ shop, especially when it comes to servers.

(that contradicts your earlier comment)

Google has been gradually moving away from C++ and Java since 2012. See this quora post with multiple references from Google employees.

https://www.quora.com/How-is-Go-used-at-Google-What-could-be...

That is not what their employees talk about at CppCon, LLVM conferences, ISO C++ meetings, Java Language Summit (yes they come around in spite of Android).

Go is mostly a Docker/Kubernetes thing.

The fact that most Google code is C++ does not at all contradict that they are invested in Swift.

Google is a more of C++/LLVM, Java/Kotlin, Python shop, than Go one.

You will even notice that it is seldom supported when they announce new server products SDKs.