Perhaps a better question: At what point in their development would Page and Brin have been interesting? Or would a couple of Stanford PhD students have gotten them an interview on that alone?
We wouldn't have counted it against them that they wanted to take on big companies. That kind of courage is exactly what we look for. When combined with rationality.
But the guys who made Twitter weren't planning to make it into a business. It was just a cool idea that they had and expanded on.