A closed-source development process cannot withstand the onslaught of open source, especially when you start with the same code base. Those of us watching the race would have to content ourselves with pointing, laughing, and buying the volunteers beer. Admittedly, users without source code will have a hard time fixing bugs or adding features themselves. Most companies today have trouble finding people who can make reports off their Access databases, let alone people who could fix device drivers. Companies who have that talent probably already have HylaFax and their preferred free UNIX chugging away somewhere.
Most customers fix problems by asking the vendor.
And no code, whether GPLd or BSD'd, can make up for a company that does not respond to its customers. Starting with known working code can give them a head start, but a non-responsive company still won't go far. You might gripe about Microsoft's quality, but the average user can't handle desktop UNIX yet. The Windows interface might not work well, but it is easy. The average customers want simple more than they want performance.