I think it actually is even more relevant today than 10 years ago, as the only real production use case I can imagine for it is specialized industrial software written only for XP that no one wants to update to w10 because of the risk of breaking production but which are running on a not supported anymore OS full of vulnerabilities. If really ReactOS achieves parity then that's a possible niche.

I remember seeing laser cutter drivers which only ran on Windows XP, but the cutters themselves were still in use and worked great.

For (ham) radio programming software which often only supports windows, getting the programmer working on reactOS seems like a win.

That was the argument back in the day too. For people/devices not looking to run Windows XP/Vista.

I don't think the metric has ever changed. What has is the scope as Microsoft continues to chug along. But, I believe, their goal is still primarily some hybrid of Win98/Win2K compatibility.

I think OP means, this project is very old, what's new about it?