There are rational explanations for this. When software fails catastrophically, people almost never die (considering how much software crashes every day). When hardware fails catastrophically, people tend to die, or lose a lot of money.

There's also the complexity gap. I don't think giving someone access to the Internet Explorer codebase is necessarily going to help them build a better browser. With millions of moving parts it's impossible to tell what is essential, superfluous, high quality, low quality. Fully understanding that prior art would be a years long endeavor, with many insights no doubt, but dubious.