Not, but it's almost certain that it was at least some factor in failure.
We all know what DEI means: "Didn't Earn It". DEI means you voluntarily dropped your workplace efficiency and capacity in the pursuit of quotas to satisfy your investors, but meant zero thing for your consumers, and they're the ones that will make your company successful in the end - the investors make it possible, the consumers are those that make it viable.
It's even worse if you do DEI in your product, not just the workplace. Because DEI is attempting to pull in minority groups that otherwise wouldn't have come to your product, and guess what? Even more of a minority of that minority is going to come around to your product just because you added DEI stuff. And at the other end, at best it is neutral, at worst, you actively removed
I think the company that focus on DEI on the products are the ones who really fail "because of it". Those who do it in the workplace simply reduce their margin of safety, by expanding their costs at no benefit. The "he/him - writes code" meme. They fail when the rest isn't quite there, and they didn't have the right people to salvage the situation. They might have gotten those people without DEI, they might not have gotten those; it's just that DEI hiring torpedoed their chances of surviving small failures.