Writing JS/TS for browsers and backend applications is an entirely different skill. The only similarities are syntax. From the organization's perspective, the developer's primary expertise is a platform/framework, not a language syntax.

The point of the article is right for the indie developer who wants to stick with one language as a "mother language" and be able to produce any kind of software in no time. For scale, it is not the case.

I'm a big fan of JS/TS, but there are absolutely significantly better choices for many backend applications.