There are a lot of reasons to kill a startup. Chief among them is that no one wants to be your customer. Another might be that despite how hard you try, you can only be average and not one of the best.
Running out of money is not one of these valid reasons. A broke company is only a temporary condition. There are a million ways to get money to feed your company. Go sell your own brand of cereal to keep the company alive. Go do some consulting. Wait on tables if you have to. So long as you can generate your own money to feed your fledgling dreams, you never have to say die.
Paradoxically, when you raise money from outside investors by selling equity, even though you have more money as a resource than ever before, the clock starts ticking. Now your monthly burn becomes very meaningful. Now you have a board of advisors driving you to make decisions you would have patiently addressed otherwise. And when you run out of cash after raising outside capital, you probably have to say goodbye.