From Googles point of view, App Inventor is more for educational purposes than for commercial Android apps. For most people, crawling is a necessary stage before walking and running. A lot of competent professional Mac programmers started out with stuff similar to "20 GOTO 10" or HyperCard stacks. There currently is a extreme lack of such toddler sized steps customized to the Mac and iPhone paradigms. However the Objective C runtime interpreter is just itching for somebody to build a nice small set of Obj C classes/objects/messages that (1) is Turing complete (minus the infinite memory), (2) can be assembled to create a variety of interesting apps (to a kid), (3) hooks to some sort of Webkit/HTML5 UI on the front end, and (4) can each be represented by a nice graphical symbol that will interlock with the objects with which it must message. Just dynamically instantiate objects and do runtime message passing down the graphical program flow using NSClassFromString, NSSelectorFromString, respondsToSelector, and the like.