There's another angle people haven't covered on Core vs. Knots. The average tenure of a core maintainer is about 3 years. In total, they've got 19 years of collective experience as maintainers. Luke, meanwhile, has 14 years of experience maintaining Knots.
Suddenly the "one guy" thing doesn't seem quite so obviously problematic, especially as experience in year 1 and experience in year 5 and experience in year n are not all created equal.
That all said, the answer really is more node options. We could explore having core maintainers living in a monastery and taking an oath of poverty and undergoing extreme training to beat out of them any ego and desire to be known as having made a mark to try to shape them into perfect stewards of a system that is bigger than all of us, or we could let the market shape people with open competition. As much as the notion of Bitcoin Knights Citadeliers (Citadelars?) is an amusing image, market competition seems to be far, far more realistic. 

