Another factor in favor of going solo is that the ratio of deadwood at your company is going to be either zero or one.
That is, if you're genuinely good at building things, you're going to build your thing quickly. There's nobody to drag you down, no slow backend guy blocking you from implementing the frontend or vice versa. Or maybe you find out it was you doing the blocking all along, which is also handy to know.
The project will go at the speed of the slowest skill the members have.
So if you're faster than your co-founder, you'll feel that as slowing you down. But the real question is whether you'd be faster at that task than them.
E.g. if you rock the backend, and are forever waiting for the frontend to catch up, you'll feel slowed down. But that's only true if you're also faster at the frontend work than your co-founder, and able to maintain that speed while doing both frontend and backend.
There's a point at which having someone else do half the work makes the thing go faster even if they're not as fast as you.
Two things. First, it signals that maybe solo founding isn't going to be your thing. Second, it cautions a career path that involves working for big companies with good job security and benefits, ideally in a department where you can be forgotten about and not ever required to produce any results.
If you remove all blockers from your path and still remain blocked, it's a good indication that you shouldn't ever place yourself in a position where people are going to notice.
That is, if you're genuinely good at building things, you're going to build your thing quickly. There's nobody to drag you down, no slow backend guy blocking you from implementing the frontend or vice versa. Or maybe you find out it was you doing the blocking all along, which is also handy to know.