This timeline is a bit aggressive for Ruby. The core of my career using Ruby was 10 years ago, and I would still call it "darling" at that point, though the rumblings were beginning. Node.js was first released almost exactly 10 years ago, and (from my perspective) over the next few years marked the first real exodus from people who had previously been all in on Ruby. I missed out on that one because I thought node.js seemed like an immature answer to a question I wasn't asking. But over the next few years, I became increasingly disillusioned with writing big software in a language without good static analysis, and was on board with the mindshare (if not actual employment) exodus toward languages like Go and Rust. So I would say it was more like 5-7 years ago that you started seeing more criticism than love for Ruby in places like this.

And yeah, as other commenters have said, Python is back due to data science / machine learning. (Though I'm hoping there will be a wave of adoption of tools like Julia and Swift for this in the near future; good static analysis will be nice for data science for all the same reasons it is nice for other kinds of software.)