It depends on your field. If you're a services company (as in, consulting and subcontracting) you're dead in the water unless you have a sales team day 0, even if that sales team is just the founder working over time. Those places live and die by their contracts.

There's a large number of small (<5) person companies that work entirely like that. They're not _sexy_ and they're never going to be unicorns, but they make a good amount of money for the people involved when they inevitably get purchased by some larger group.