It's important to understand that something being not-diverse doesn't necessarily make it an echo chamber.

Let's say you're working on something big and important, let's say a manned mission to Mars. You get the best people available, of course, and you get them into one room and you're brainstorming. Everyone competent will think along the same lines towards the same goal. You'll be using some kind of rocket propulsion, you'll need life support to keep the crew alive for years... all those smart and competent people will disagree on details - do we launch straight from Earth or do we do multiple launches into orbit, assemble a larger spacecraft, and fly that from LEO to Mars? How many crew do we need? etc., but the group still has absolutely zero use for truly diverse points of view like "Mars doesn't exist", "this garbage", an unironic flat earther, or a diversity consultant who keeps bitching about the spacecraft not being wheelchair-accessible.

Of course, there's an exception to everything, so once in a while, someone who goes completely against "common knowledge" is proven to be right. Like Ignaz Semmelweis, the doctor who came up with early germ theory and managed to drastically reduce childbirth mortality by making doctors wash their hands. Everyone thought he was crazy, the "scientific consensus"-following people first laughed at him and then they had him institutionalized for ranting about bacteria and shit because it sounded like nonsense to them, and he was right. But, when talking about exceptional people like this, we need to remember that 1) the guy actually demonstrated that his methods worked beyond any doubt (he really did reduce mortality from like 15% to a fraction of a percent), and 2) exceptions like this are exceedingly rare and 99.999% of all "diverse viewpoints" are horseshit.