The key problem isn't if an application is open source, or even it's usability - it's the incumbency problem.
Name one general consumer application for windows which wasn't being used ~5 years ago - even if it is non open source. I can only think of Firefox, games, and maybe some IM client software.
Even usability disasters (eg Vista) win huge numbers of users when they are the default choice.
When new niches open up (eg, web applications), open source apps have proven to be just as usable as commercial apps. Eg Wikipedia and Wordpress.com are both in the top 10 sites world wide, and both are open source (ie, the apps themselves are open source, not just the infrastructure software).
The key problem isn't if an application is open source, or even it's usability - it's the incumbency problem.
Name one general consumer application for windows which wasn't being used ~5 years ago - even if it is non open source. I can only think of Firefox, games, and maybe some IM client software.
Even usability disasters (eg Vista) win huge numbers of users when they are the default choice.
When new niches open up (eg, web applications), open source apps have proven to be just as usable as commercial apps. Eg Wikipedia and Wordpress.com are both in the top 10 sites world wide, and both are open source (ie, the apps themselves are open source, not just the infrastructure software).