I can’t help but see this an internet version of the free trade vs protectionism debate that has been ongoing in the sphere of economics. On the one hand you have domestic business and industry doing everything they can to protect there entrenched and largely outdated business model. On the other you have the consumer and general public who reaps the benefits of an open and unrestricted internet.
It has to do with the core android audio drivers. Dj type apps require very low latency drivers. Until the most recent versions of android the drivers were simply not responsive enough. Much improvement has been made but unfortunately the masses always seem to be 2 or 3 versions behind current in the android world so there isnt really much of a market for dj type apps yet.