That would be a very lucky outcome, I agree. But it's not so hard to imagine that 10 engineers could produce something that looked impressive enough to investors to throw $25 million at the idea and tell them to pay themselves $3m a year and hire 20 more at a somewhat lesser sum, in the expectation that they would be very profitable a few years later.
Even with one of the most common software businesses, software consulting, you could reach this amount with 10 people in a fairly straightforward fashion.
10 software engineers at say a salary of $100,000 a year. Consulting rate at 3x would be $3M a year.