To elaborate a bit more: open source is about 'symbolic capital' — it's about building a reputation that says, 'I can write code at this level.'

Commercial closed source, on the other hand, is about 'I need to make money by writing this.'

Generally, open source projects tend to have less code written over time, especially when the contributors aren't depending on it for their livelihood. But with commercial closed source, it's not uncommon to have to write 60,000 lines of code per month.

On top of that, open source rarely has to deal with requirements changing dramatically mid-development. With closed source, requirements often shift from the original plan, and you end up compromising code quality just to meet those changing specs. As a result, if you're comparing purely in terms of logical completeness, open source tends to be better.

For example, singletons are rarely used in modern open source, but they're still pretty common in commercial code these days.