you are right, but there is a paralell. when it comes to hiring programmers i prefer people who are good at programming in general and at least familiar with two or more languages. because those who are very good at only one language and have never touched another will have a hard time learning a second language, and, will also have a hard time getting to expert level because they will miss out on that additional pwrspective that other ways of doing things provide.
same goes for knowing multiple web frameworks like angular and react for example, to be even more specific.
greetings, eMBee.