This is strange to me. Many universities, including mine, avoid interviewing applicants with a PhD or postdoc from the same institution to which they are applying.

Being forced to upend your life and relocate far away every four years is also not a positive aspect of academic life.

You should try working for the State Department or the military!

Military officer corps at least comes with a insanely generous pay+benefits package when compared to PhD and post-doc. And the bar is lower and work easier for most positions.

You graduate, get an external, preferably foreign post-doc, and return to interview for the next available position. Problem solved.

At least in my department, this will not work as long as the applicant's supervisor or dissertation committee members are still in the department. The crux of the issue, in my mind, is that it is hard to have candid and unbiased discussion about a candidate when the supervisor / dissertation committee is part of that discussion.