There's an interesting trend of open source clones of popular products. Most recent one that comes to mind is Athens [0] which is an open source clone of Roam Research.

The business model is always that people who really want it for free can self host, and people who don't want to deal with the hassle will pay for hosting. Seems like a reasonable strategy to me.

[0] https://github.com/athensresearch/athens

anyone know of a GitHub list of open source clones of popular products?