I'd say half of our successful businessmen did it solo until they needed funding and materials along with the manufacturing team.
It's not as rare as you think but you can't succeed alone when you need other industries and employees to make the business grow and expand outside of your area.
Make your fortune and then reward your employee's so that they aren't living in poverty doing their best for your company.
There is more than enough money investment available that you don't have to prioritize Investors unless your idea is absolute shit. π
Buy Real Estate and rent it out to your employees at an affordable fee is a very easy way to take care of your team.