And a good engineer usually does not make a good salesperson. Starting a company does not make a good engineer better nor does it guarantee a better path in one's career. On the contrary I would dare say.

That's obvious to everybody. The point is, co-owning the company you work for has some fundamental advantages. By the way, this wouldn't be true in a perfectly competitive market, it's only true thanks to market imperfections.

For example, in the company I work for, sometimes I slip into the mode of feeling like I "own" the product we're making, making an extra effort, being emotionally invested, etc. But then I remember, I would just be a fool who works for his employer for free. Also, achieving change requires a lot more effort and often fails, which can be demotivating. In general, I feel like I could run things substantially better if I had the power. Seeing the mediocrity at fairly successful companies makes me really think about working at a startup.

I've been called a good Engineer. All my companies I started failed.

This hits close to home.

Luckily for you, there’s plenty of us stuck in other depts (technical sales, customer services) that still understand a lot of the technical stuff while being more used to working closely with customers. Try finding a company buddy, they might be closer than you think.

Lol. This is terrible advice.

Starting a company does nothing to prevent others from stealing your work. Just puts more effort on the business owner to source business and protect their IP.