The first three things you mentioned are still requirements for a successful startup. They're not sufficient, as you've pointed out, but if you have those three

The first three things you mentioned are still requirements for a successful startup. They're not sufficient, as you've pointed out, but if you have those three then you're off to a decent start. Building a successful company is about far more than just building a product. If you're one of the lucky few that find product-market fit, you still need to scale the company and build up an organization that execute on the opportunity that exists. That is mostly a people and leadership problem, and not a technical one.