What we really need is well-built open source software base with flexible and well-documented plugin SDKs where people can just vibecode their own extensions on top of them. The software needs to be designed from scratch expressly for the purpose of being extended in this way, and the SDK should place appropriate limits to allow multiple extensions to be combined easily.
Otherwise, there is too much you have to do right before you have a suitable software base to start building your extra personalized features on. Building on existing open-source software (not designed to be extended on) isn't great either because you would need to merge any changes from the original software into your fork, as opposed to a purpose-built SDK that would better tolerate plugins on different base software versions.
I'm working on this for gaming but the idea is really applicable to any kind of software, if the goal is to allow people to easily create and run personalized versions of them without as much effort and chance for things to go wrong.
In short it's striking a careful balance between giving game mods the flexibility to make whatever they want, and not giving them too much low-level access that it leads to incompatibilities with other mods.
In my case, I am not letting mods extend game code directly because I have additional constraints that require mods to run on a restricted runtime. In some other games, mods DO extend game code directly and I am most familiar with Minecraft. The problem with Minecraft is that the modloaders are community-made; the game itself isn't designed to support mods so there isn't a stable modloader API between versions. If that one issue is fixed it would be possible to effectively vibecode your own version of the game and not have to reinvent the wheel by coding up the base game first. You'd also have your changes persist indefinitely and benefit from base game updates. And like I said, I think this is a powerful pattern that can be applied to plugin systems in general non-game software as well.
Otherwise, there is too much you have to do right before you have a suitable software base to start building your extra personalized features on. Building on existing open-source software (not designed to be extended on) isn't great either because you would need to merge any changes from the original software into your fork, as opposed to a purpose-built SDK that would better tolerate plugins on different base software versions.
I'm working on this for gaming but the idea is really applicable to any kind of software, if the goal is to allow people to easily create and run personalized versions of them without as much effort and chance for things to go wrong.