This is a self inflicted injury in my opinion. Intel wanted to keep Optane within its ecosystem, and even within that ecosystem, they dictate that only certain chipset and processor will be able to use it. The high cost and high power consumption limited its use to mostly desktop or just a small cache in mobile device. So from the consumer standpoint, it is not surprising it failed.
From an enterprise standpoint, I feel those restrictions are not the main issue, but I feel the cost and high power draw may have done it in. And as enterprise starts to use AMD and ARM based systems, it will further limit sales.
Overall my opinion is that Intel dropped the ball on Optane. I don't always follow the news on Optane, but I was quite excited about it at launch. It was a promising replacement for NAND based SSDs, but it is not without its problems. Intel could have worked on improving it, but I don't think much was done to address the shortfalls.