I've always been a proponent of being a solo founder, but a few years ago I went down the path of starting my (current) business with two other co-founders.

One I fired after a short while as he wasn't carrying his weight.

The remaining co-founder has been a God-send. In January, I was diagnosed with late-stage cancer, and he took over the reins. He stepped up in a way I couldn't have ever imagined. Days I was suffering from surgery pains or (daily) chemo, he kept the ship afloat.

Everything OP says is correct, but one of the things my co-fonder gave me was an unplanned plan for the unexpected.

Without my co-founder, I'm not sure we'd have survived.