-So do you have experience with SAS?
-Yes, but mostly I model in R. They are sister languages.
-So how much SAS, how much R?
-Mostly R as it is widely held to be a superior language
-But SAS you can do more with!
-Ahh, if Big-Famous-Tech-Company-X wanted to do stat modelling they use R, not SAS. Again, anyone who does statistical modelling knows this.
-But we pay for SAS
-Yeah, sorry about that...
It's like asking a carpenter to built a cupboard and he answers: "I'd rather build a shelf, it will hold your dishes just as well."
Likewise, who would want to use an inferior language or library when superior ones exist?
My guess is that the existing codebase is in inferiorLanguage, and it would be a massive pain in the ass to rewrite it in superiorLanguage.
The carpentry analogy doesn't really work here because you can stop using the rubber mallet at any time. You can't just switch frameworks or languages when you feel like it.
Its also like deciding to hire an HR guy based on what brands of keyboards or pens he's used.
I get what you're trying to say and I agree 100% it's foolish to make hiring decisions primarily on having X years experience with Y technology but let's not pretend all technologies are as interchangeable as a Craftsman screwdriver vs a Husky one.
Just because someone has a lot of experience working with wood doesn't mean they can do anything with wood well (at least not without sufficient time). You probably wouldn't want Antonio Stradivari to build you a house or Bob Vila to make you a violin.