With iPhone's they get around 4-5 years of updates compared to the 2 years promised with Google's devices.[1]

Buying into iPhone development might be more expensive upfront, but you get a longer update period (which is obviously important for developers).

I paid around $725 USD for a 2012 Macbook Pro which can develop for iOS and it has 16GB of ram, an SSD and a hard drive for time machine.

[2]https://support.google.com/nexus/answer/4457705#nexus_device...