Earlier quoted context omitted.
Not that I disagree with you, but sadly, most companies don't seem to want to train people anymore. They rather push that responsibility to either universities or the applicants themselves. In fairness, I do think that someone who is very comfortable with a language or framework will be able to do things much faster than someone who isn't. Considering how quickly people change jobs nowadays, I can also see how compan…
Define "much faster." I am seriously trying to think of a developer I'd describe as competent and smart who could not pick up a new language or framework with sufficient understanding to be minimally productive (fixing minor to moderate bugs, contributing to new if simple features) inside a week or two. If that's not fast enough, something has gone terribly wrong planning the project.
Someone who knows the ins and outs of their language won't have to look up or learn new stuff as they go for example. This isn't even necessarily restricted to languages or frameworks, if you've done something similar to an assigned task, you would likely have already encountered certain pitfalls and know the best way to complete the task.