Your evidence for app incompatibility is... variant icon art and placement on a bunch of pre-ICS phones that aren't sold anymore?
I mean: it's true, Google failed to enforce a layout for the original Android buttons (Home, Menu, Back, and Search). And device manufacturers put them in different places (sometimes omitting Search entirely) and used different art, and that was bad. And Google fixed it with ICS (a year and a half ago!), which uses soft buttons exclusively. So sure, it's a valid point.
But to argue that somehow you can't write a compatible app because Samsung put the back button on the other side from Motorola is just ridiculous, sorry. Get a better example.
I mean: it's true, Google failed to enforce a layout for the original Android buttons (Home, Menu, Back, and Search). And device manufacturers put them in different places (sometimes omitting Search entirely) and used different art, and that was bad. And Google fixed it with ICS (a year and a half ago!), which uses soft buttons exclusively. So sure, it's a valid point.
But to argue that somehow you can't write a compatible app because Samsung put the back button on the other side from Motorola is just ridiculous, sorry. Get a better example.