Because none of us knows Dart, nor are any contractors likely to know it. Also, based on research I did before starting a cross-platform project, you still end

Because none of us knows Dart, nor are any contractors likely to know it. Also, based on research I did before starting a cross-platform project, you still end up writing a lot of native code on each platform when using Dart. At that point, you might as well just write native apps.