It'd be an odd result, because there are big companies in other fields that grew by bootstrapping and then reinvesting profits. For example, as far as I can find, Wal-Mart took little to no investment before the IPO. I wonder what makes tech different? Is it somehow more capital-intensive, contrary to the usual assumptions? Or is it that it's a lot easier to get investors in tech, so people aren't forced to bootstrap? Or that alternative financing options are harder to use in tech (no equivalent to Wal-Mart's strategy of opening new stores by taking out loans with existing stores as collateral)?
Some interesting data to see would be: what's the biggest tech company that has never taken outside investment? Are there any significantly bigger than 37 Signals?