A lot of claims in the article.

IDK if the WS-15 failed or is "two decades" behind. I think we just don't know, but we do know that it is that they have achieved the ability to deliver, in mass, third-generation single-crystal nickel-based superalloys. That's a strong proof point.

As for commercial, China can/has grant a sizable portion of the C919 to domestic engine producers ( I think AECC has this contract ) that allows for a lot of capital and practice.

I would not be shocked if China demonstrates highly competitive engines in the late 2020, maybe with a few setbacks and iterations. I would also not be shocked if they started demonstrating engines with some characteristics slightly better than the Western manufactures in that time period (or maybe a little later).