Why do people in the software business feel the constant need to compare it to other fields? I don't know of any other profession that does.

I think the restaurant analogy is flawed because the accounting for fixed and variable costs doesn't jibe. You can bootstrap a software company with minimal investment - as YC itself proves, but restaurants require a building, cooking equipment, tables, chairs, dishes, etc. Plus, you can start a software business in your spare time - something I doubt too many restaurateurs attempt.