Well sometimes shit happens, but it's hardly frequent enough that it should be considered in this particular risk assessment.LOL, hints. There was one promising game dev in Turkey who had a lot of family members die in an earthquake a few years back. Another one, who had probably the most exciting game for me at the time disappeared completely w/o explanation after complaining about working two jobs for a month (he was posting weekly dev updates as well).
The more you drag out the game, the more likely something unexpected will happen.
And when it comes to the second point, well as hard as it may be to accept, game devs are still just humans. It takes a lot of patreon support to be able to fully support a full time developer in a western country. And working two jobs is just hard. There's no way around it, it's stressfull and draining. And when push comes to shove and you just can't continue this way anymore the thing that you well abandon will be the job that doesn't pay the bills as opposed as the one that does. If you want this to not happen, the only thing you can do about it is to support the dev in question yourself.
There's of course also the third variant. The dev who managed to go full time and who over time starts to slack and release slower and shorter updates. There's lots of potential reasons for this. Maybe they're burned out from working on the same project so long. Maybe they are scared. Their entire livelihood depends on the patreon support for this one game. If it gets finished who knows if the patreons will stay. Look at 395games, the developer of "The Mist". He's shifted right over to a new project and has delivered regular updates in a high visual and technical quality for that new game and yet his patrons have only continued to decline since the release of "The Mist", since a lot of people don't like the characters as much as they liked the ones in The Mist.
Not that that's any excuse to start milking and stalling your games development, but it is a sensible fear that is rooted in reality.