I somewhat agree. Good game design requires a great idea, but more than that a lot of iteration. If you are working solo you need to hold the implementation and design in your head, which is incredibly difficult. Iteration is slow. You need someone to bounce ideas off of.

The best indie combo is a programmer plus a designer/artist in my opinion.

Alternatively, you can spend a very long time iterating solo. Most don’t have the runway for this.

This is also why big studios produce technically impressive games with mechanics seen thousands of times before. The production risk is much lower for “make spectacular assets” than for “come up with a novel game mechanic”.

Impossible but necessary. It's the big difference between an engine programmer and an indie dev. The latter needs to wear multiple hats to get something out while the former can specialize and work within a team of other specialists.