With a response time like that it seems like antivirus software is becoming increasingly irrelevant.
I don't think it's a good argument - what about defense in depth? Don't antivirus packages have heuristic protections? Or are those, in general, useless?
The cases I've read about were of the form "app A asks app B to do something it can't via the Intent system". That sounds scary until you realize that a standard example of this is an app that can't access the network sharing something via email. In other words, app A has transferred control to app B and what the user does (or doesn't) decide to do with app B is their choice, not app A's.