I'd be somewhat skeptical of anyone trying to product manage an open source project, and I think unless you were a truly exceptional product manager, most contributors would perceive your contribution as net negative if you tried that. The point of open source is people work on the things they want to work on (for the most part, obvious exceptions apply) and via a Darwinian process, what survives is the result of the best ideas of the people who stick it out.

Open source contributions I've made have been mostly because I need a certain feature or there's something that doesn't quite work right etc. Eg recently I took up qubes os. I like using the i3 window manager, and it had some problems on qubes, so I made some small contribution (I can't even remember what it was now) to fix that.

The normal PM process wouldn't work, but I think normal PM processes are broken anyway. It also wouldn't cover all the wonderful small features, ports and fixes people like you contribute.

Any notion of "setting priorities" would go right out the window. It would have to entirely be about giving gifts, which is what open source is based on, anyway.

"I talked to 5 of our users about this problem. Here's what they said in summary, with some pull quotes. Here's how 3 other libraries solve this problem. I added 2 more ideas, made a table comparing all of them. Here's the 1 I think is the best, if anyone wants to make it."

Then it gets picked up or not (probably not lol). But no "influencing" past that. The influencing is just doing useful research, idea generation, and sharing it.

if you can herd a cat, you can herd a sheep

They require different approaches.

The best way to herd cats is by a laser pointer: show a clear, shining goal, and you don't need to give more directions.

With sheep, you need to run circles around them and so drive their formidable grass-cutting capacity where you want it to be, slowly.

Nice analogy. I like that. For the laser you likely need to show an indicator for the distance to the bright red spot, and break it into measurable chunks (like a roadmap) to which actionable steps can be attached. Tbh a cat won't do anything with that, but to the feline breed of FOSS developers it may help to keep (and understand the importance of) product focus. Although you might just focus the bright spot on farther away objectives when the felines get closer to it, to refocus their attention.

Bright light in the distance works for me. A lot of the interest is in the path finding process - dead ends and cycles included. A bright light in the distance that someone else has broken into measurable chunks is totally unappealing.

Like JC said - you can shove your roadmaps where you like, many people contribute exactly because they're sick of roadmaps and product foci.