Blender and KiCad are both great examples of what's possible. They were technically reasonably complete but absolutely awful to use - until they started focusi

Blender and KiCad are both great examples of what's possible. They were technically reasonably complete but absolutely awful to use - until they started focusing on UX and features desired by industry professionals. In just a few years they went from being cute open-source toys to being serious alternatives for the expensive proprietary market leaders.