Is difficult code better written by one person instead of a team?

This is a great question and I think the answer is it depends on the problem.

For example, multiple people driving a single car often a bad idea.

The more complex the problem, the more difficult it is to coordinate communicating the solution. And no team is sufficiently organized to tackle certain problems given the implications of Conway’s law.

Though, the plasticity of a singular brain may be sufficiently organized to tackle certain levels of complexity.

Programming is really a one-person job. I've been in the business thirty years, but I came to this conclusion after just fifteen.