This opinion doesn't seem to be backed by much evidence.
The single-thread async-by-default execution model that nodejs shines at is brilliant for io bound tasks, like REST APIs.
Go is fine and has it's strengths, but is by no means a nodejs killer. It's another tool in the toolbox.
Reducing one of the most popular and effective modern server-side languages to "react server side rendering" is inaccurate, at best.
It also ignores node's massive use in the embedded space, desktop (electron, nwjs, etc...) and emerging data science space.
When I'm looking for a backend for my next project, it would be very hard to convince me to move backwards to python etc...
Those feel very legacy to me. Slow, apartment threaded model with blocking io, tons of context thrash from thread switching, bad package management, difficult environment configuration, etc...
I'll stick with node until there's another truly innovative technology that comes along.