Good post, though, I should point out that some companies might not have the time to let a developer get up to speed on a particular technology, they they haven't used before.
For established companies with legacy code bases older than two years, there is always going to be a getting up to speed period. To pass smart people over because they chose the wrong buzz word for the focus of their last job (or the buzz words recently changed) is a great way to always have people that need to get up to speed on your team.
Of course, that's the relaxed end of the spectrum. At a freshly-minted startup, I wouldn't be surprised if spending a week familiarizing yourself with the project's codebase (let alone the language/framework) was pushing it.