Dude, this is _Hacker_ News. Who cares? This is cool!
Also: Their latest release was 0.3.17 in 2014, with the 0.4.0 release candidates coming out late last year. So it hasn't been 10 years between releases, but around 1.5 years.
While usually I'd agree with your snarky comment, I am genuinely curious about this too. It's not some yetanother.js hacked together in a night but years (decades!) of man hours.
I've done similar projects myself. The thing that pushes people like us is that it's fun and challenging work! There really doesn't have to be anything else.
I believe the Russian Government has considered/is giving them support so that probably helps. Otherwise, a passion for the project and love of the craft most likely.
It's almost all a volunteer effort. They get the odd donation from time to time, and they had a crowdfunding campaign, but they really don't get that much money.
ReactOs is still in alpha stage, so I don't think it's ready for everyday use. Also it has not been 10 years since the last release, it has been 10 years since the last mayor release.
I'd really like to know how many people are actually using ReactOS for another purpose than testing or developing it.