Open Source is one person

Has anyone seen any stats on what happens to a single maintainer project when said person is hit by a bus (or meets some other demise)? With that many data points, there should be enough of them by now to study it.

Is the project taken over by another, single developer? Is it replaced by a similar project? Does it just go away?

Here is one data point.

I bought ASIO Link Pro (software) something like 10 years ago to help route virtual audio devices on my system. The author sadly died and eventually the license key server went offline rendering it unable to start. His nephew looked into it and eventually made the tool free after a year or 2.

I stopped using it after the license server went offline because I still had to record videos. I ended up solving my problem with hardware, but that tool was extremely helpful when I used it for years. It was around $40 at the time. It's one of the few pieces of software I've purchased and felt really happy about it.