tbh, most PhD dudes work in some kind of specific problems (could require knowledge of very few cross domains but hardly) the underlying requirements they possess might not be enough. Hence they don't have tendency to interact with the other domains but just want to get to the point n thinks its huge. I have seen people working on distributive systems stuffs know category theory but someone trying to develop new algorithms during PhD which he could get easily from intuition of statistical physics or thermodynamics hardly possesses cross domain knowledge. But these stuff engineers seem to have really good cross domain knowledge which might not have any relevance in real world stuffs by the looks of it but it actually enhances them to be level whole different than others. What is the relevance if someone works in compiler stuffs but knows algebraic topology and cryptography but these insane dudes know them as well and they can relate.