I think all the "a few days" and "a week" stuff that generates these kinds of debate is a total red herring. Yes, it's hyperbole. But it's also true that people with experience successfully applying a bunch of different technologies are great hires onto a team using a technology they don't yet know. It's just a process measured in months rather than days. But if you need to hire someone because you have something that needs to get done this week, then you've already screwed up.
And then it gets back to my other argument. Are you going to pay someone the same that doesn’t fit your technical needs as you would someone who does? If you pay them less, are your raise policies going to allow you to get them to market value once they do have the skillset or are they going to end up job hopping?
Personally, I would not take this into consideration when deciding how much to pay people.
I recognize that there are a lot of different niches in our industry, and presumably in some of those niches this narrow focus on what technology is being used makes sense, but that hasn't been my experience.
In my experience, you want people who are both pragmatic and flexible about learning, evaluating, choosing, and teaching others new tools.
I do recognize this may be a somewhat privileged view. I think I've been fortunate to spend my career in organizations where software is the profit center rather than a cost center supporting the rest of the business. My experience is that these companies have focused their hiring, compensation, and performance expectations on fundamentals and figure-it-out-itude rather than any specific technology stack.
