If people want to find software, they search GitHub. If you self-host a forge, no one will ever find your software unless you’re a preestablished big name (like Blender). To avoid throwing your code into the void, you’re pretty much forced to mirror with GitHub, at least.

To avoid this and make smaller forges as a block a viable competitor, there needs to be a singular network that solves discoverability and lets you find software from any host – like ForgeFed would.

There’s also the concern with the friction created by requiring newbies to log-into a dedicated forge for contributions (which ForgeFed solves), but I reckon that’s a secondary and related concern.