I think you've mis-interpreted "Given enough eyeballs, all bugs are shallow".
When you have more eyeballs on a project, there is a higher chance that some of those eyeballs have the technical expertise necessary to find/fix a bug. For a proprietary/commercial project, the pool of talent available is only what you can afford but for a free/open-source project, the pool of talent available is free abd very very large provided that you can attract it.
When you have more eyeballs on a project, there is a higher chance that some of those eyeballs have the technical expertise necessary to find/fix a bug. For a proprietary/commercial project, the pool of talent available is only what you can afford but for a free/open-source project, the pool of talent available is free abd very very large provided that you can attract it.