I mentioned the main reason why, but I'll expand - these developers will loose sales as MAS become more popular and people ( new users, less savvy users particularly ) stop looking outside for mac software. These types of software won't be developed if they can't be sold - that is, software will only be developed if it can get in the MAS - and conforming to Apple requirements ; OSX will suffer as a consequence: Ultimately too many developer restrictions hurts innovation, and reduces overall functionality. IMO - I've seen this on IOS - less varied range of software than on other smartphones ( i.e., an App can use less of the phone's hardware than other platforms, and general API restrictions ) - simply because of apple restricts.