what is becoming a common problem in FLOSS projects: lack of funding.

It's usually more of a problem of expectations. A lot of people just seem to not understand how it works. For example, if this guy wanted to monetize incron he could have started do general consulting and used the incron website and an eyeball attractor or credibility builder. Also, getting some sort of downstream going (which I agree wouldn't be easy) would help offload the work by giving other people an incentive to contribute to the code for you.

It's also worth mentioning that some projects just eventually plateau in terms of new features or bugfixes. It eventually gets to the point where you're basically just keeping the lights on and the actual work involved in maintaining something is pretty negligible. For example coreutils releases a new version about once a year and if you look at the changelog a lot of the changes are just about fixing how things get printed out to the user. That's for a toolset almost everybody uses every day.

Looking at the changelog for incron it looks to be in a similar state. Reading through the last year's changes it's mostly just rudimentary "well this isn't working exactly right so I fixed that" where all the bugs seem like they were pretty shallow. The exception would be the recursive watching which sounds new and non-trivial.

Anyways, point being that there are ways to monetize this and it's not like a project like this should monopolize the maintainer's time. Even if it did for some reason, getting downstream involved might lift the burden.