Interesting that you are so fixed and unimaginative with integration in scientific fields.
That's because I'm too familiar with some of those fields to imagine that they can be integrated. Your point about overspecializing is VERY interesting, since as far as I can tell the only people touting the benefits of cross-field integration are the people who are highly specialized in a particular field and want to be able to speak authoritatively outside of it.
There aren't many generalists in the world now, but you don't see them showing a lot of support for that idea. There's a reason for that: when you spend a lot of time studying multiple disciplines, you get a firsthand look of how fundamentally different they all are, the different methodologies, the different contexts, the different applications. It's much easier to think that, say, quantum gravity might have implications for geology if you don't actually know anything about geology.
This is because geologists and physicists study COMPLETELY different things that only overlap on the conceptual level; they collect their data differently, they experiment differently, they come to different conclusions on different subjects and for very different reasons. The few ways where physics dovetails into geology treat geology as the "senior officer" in such cases; you cannot, for example, make accurate predictions about a volcanic eruption using fluid dynamics alone, you would first have to account for empirical evidence gathered by geologists about what kinds of things happen during a volcanic eruption. Once you do that, you're no longer studying geology, you're studying fluid dynamics in a geological context.
Simply to dismiss interested parties because they dont have a PHD in a certain field seems counterproductive.
It seem that way, but it isn't. That is, in fact, the entire purpose of HAVING a PhD in the first place.