All these companies you listed using it with Rails and that part of the ecosystem is alive and well, but I'm not interested in it.
A few years ago Ruby ruled the DevOps/Cloud space(which I working in), a lot of tools was written in it, but with the dawn of containerization, its former glory starting to fade. Docker, k8s, or even the new GitHub CLI is written in Go. While I am happy to write Ruby code, I can't expect the same from my colleagues.
While professionally I don't think I will continue to use it much longer, I still planning to keep up with it. Before the lockdown, I started teaching Ruby at a local meetup group, and I can't wait for Ruby 3.
I am thinking someday Crystal post 1.0 would be able to put up a fight in that space.
HTTP/2 is essential if you want good SEO which makes Rails a non-starter for many projects already
And sooner rather than later you are going to need a load balancer anyway.