With LLM, Bun can ship new features effortlessly and bundle many features directly into the runtime, which could be implemented by third-party libraries.
While this is more convenient for Bun user, this development approach just steals the time-tested designs of these open-source libraries. By offering simplified bundled APIs, Bun diminishes the value of contribution on those libraries.
As a general-purpose runtime, Bun cannot continously improve on every one of these domains in depth; it can only provide the most common functionality. When changes are needed, developers also cannot easily patch or customize the interfaces bundled with the Bun runtime itself.
If Bun becomes widely adopted, its APIs could effectively become locked in. That would not be healthy for the ecosystem.