I was mindfully advised on the reality of the marketability of an interdisciplinary PhD -- it comes with risks, but they are apparently somewhat mitigable as long as your scholarship and teaching experience are still marketable to a defined discipline once you are on the other-side of the PhD process (as mitigable as possible in an overall fraught job market, even with a "normal" PhD in hand). Stanford's Modern Thought and Lit and UCSC's History of Consciousness are really the only two ACTUALLY interdisciplinary programs I've found that are inherently interdisciplinary enough to really fit my needs. I've kept an eye out for where those alumni have ended up. Often I've found that departments like to market themselves as interdisciplinary but then I ran into hard walls when trying, for example, to integrate elements of STEM/sociology into potential research within an english department, or elements of sociology/literature into potential research within an STS department. The precedent simply isn't present in either discipline, i.e. the scholarship of present faculty in the field across the board.