This results in yet another opinionated framework in which that particular developer is extremely prolific. That developer then keeps making massive changes to the framework, deprecating and renaming parts every so often. At some point other engineers, who initially had been excited, get tired of the tyranny, rebases, rewrites and having to fix their functionality broken by framework changes. Then, the opinionated developer gets into disagreement with the management (that is getting more and more concerned by the constant churn and lack of new features). Being up to speed and fully convinced that he is the most prolific in the team, he decides that the management is unreasonable, easily finds another job and abandons the project. The codebase dies.
Sure that's one possible outcome if that developer is a poor leader.
The other outcome if that developer is a good leader and interested in developing a community is that a community builds around the core foundation that was laid and begins to take a life of its own.
Look at React. Started by a single opinionated developer who laid the foundations and built a prototype. From there it's taken on a life of its own and evolved. It was not designed/built by committee from day 1.
