I wonder if financial/monetary incentive would change this. I don't think it would personally (because putting a value on your free time/mental load/time you can spend with your loved ones doing something else away from the PC is precious)
On the flip side... $500/mo? $1k/mo? $5k/mo? I'm sure most projects that go "defunct" open-source-free-no-financial-incentive-thanklessly-help-build-something could probably find "motivated maintainers" for $3k/mo on average? Internationally?
Is the "capitalist" answer "this repo and all of its efforts are not worth $3k/mo to the open market"?