I think the problem with supporting "all those Android devices" is the long tail Android has [1] once you get past supporting Samsung/Motorolla/HTC devices.

[1] http://thenextweb.com/insider/2015/08/05/this-is-what-androi...

Samsung is bad enough. Take a look here [2]. Click "Tablets" and then choose "Galaxy Tabs" as the product.

I'm sure a lot of the devices are similar at a hardware level, but still, the sheer volume of them is ridiculous.

[2] http://www.samsung.com/us/support/downloads