When you start a business, your costs basically fall into 3 categories: initial costs (like furniture and stove-tops), fixed costs (like rent and bare-minimum employee wages), and variable costs (like raw input ingredients and additional labor to handle additional business).

As long as your revenue is growing each month, and you're making money on each individual sale (as determined by your variable costs), you'll eventually achieve profitability.

When I say most new businesses have no fundamental flaw in their business plan, I mean that most businesses make money on each sale (e.g. they're not selling burgers for less than the cost of ingredients and the labor to prepare it), which is not that surprising. What is perhaps surprising is that the business is also usually growing each month and they're on a path to eventual profitability, yet they run out of money and fail anyway. When starting a business, you're not convincing investors and debtors that your business model is sound (most are), but rather, that your business model is more sound than most other businesses that they can invest in.