Yep. Here and on reddit people are happy to say "we hire for programming skill, not framework or language knowledge!" and they may be right.

However, almost every time I have been rejected or offered a job and given a reason has been for a lack of domain knowledge (or in the latter case, possession of that knowledge!) of a particular framework or language.

True, but as a programmer, I believe you have to at some point start filtering out jobs that are hiring for <insert technology>. That doesn't leave many jobs and one has to be willing to look long and hard for them, but when you find them, you'll be more satisfied.