zlacker

In order to build a good email client application, you need more than just software engineers. You need product managers, designers, usability experts, internationalization experts, accessibility experts, tech writers, manual testers, etc. For whatever reason people with those skills tend to be less willing to contribute free labor to FOSS applications than software engineers.

>>nradov+(OP)
That's a great point, too. Software applications are more than the code in them. All those other folks are required to make an application good. I think the "whatever reason" for these people is the same as for the engineers, though: they gotta pay rent, and working for free doesn't do that.