Like I said,
Without wanting to sound condescending,
If you have to ask why I prefer open source, then you're not going to understand
No, the vast majority of people don't have the skills to tinker with source code
But there's a whole heap of other stuff they can do
Plus there's the piece of mind that comes with running an open piece of software
If the Mozilla Foundation went bust tomorrow, Firefox would live on
If Opera Software went bust tomorrow, Opera would die