I don't think this is really a black-and-white sort of situation. I only meant that it becomes an indicator for investors to quickly decide what it is that they're looking at. Solo founder, no customers? Probably weaker than a group of founders with no customers or a solo founder with customers.

For whatever it's worth, I don't think that it makes that much difference to success; but I do think it makes a difference in your chances of getting funded. I don't see those two things as necessarily related.