* Build products
* Sell products
* Recruit
* Build rapport with customers
* Evaluate business models
Most of that is ability. Few people have ability in /all/ of those directions. I've seen people who are even competent (not great) at all of those launch successful business after successful business.
By "successful" I don't mean billion dollar unicorn. I mean businesses which employ tens (or hundreds) of people, have millions in revenue, and last indefinitely.
This stuff isn't rocket science. If a Fortune 500 make widgets, and you make higher quality widgets at lower cost and make people aware of that, you'll run a sustainable business.
As a small business, on one hand, you'll have slightly less access to distribution and marketing channels. On the other hand, you'll have a much leaner cost model (no multi-layer executive hierarchies to sustain). Your team will also be much more focused, productive, and agile. You'll also be more risk-tolerant. All of those provide competitive advantages.