Servo was a much more modular effort.

1. we would get a lightweight (modular) electron alternative. This would have helped rust gui ecosystem a lot, just like wgpu helps rust gamedev scene.

2. Probably have more variety in browsers as everyone can now reuse servo components to make their custom version of firefox. Imagine all the linux distros which reuse gnu/linux, but have their own philosophy of package management, updates, mutability etc.. We could have had the same sort of varieties in browsers for different usecases.