I think that the ability to learn adjacent skills (and I'd call fintech and physics PhD adjacent) is a function of domain expertise. For instance, if I were running an automotive body shop I'd put the expert hvac technician slightly ahead of the quant in the "how quickly they'll pick it up" and I'd put either ahead of the person who's never run down to the end of the "obsessive about a subject" maze. For lots and lots of kids, that "obsessive about a subject" focus comes naturally and often is beaten out of them by "please go back to your data entry task; we're not paying you to find weird buffer overruns while speed-running mario brothers 720"