Not disagreeing, but answering the question of are all phones ARM: no, there Intel too. Source: had to add Intel build support for our Android SKUs to run on said phones. Some Unity stats from about 6 months ago indicated:
ARMv7: 98.1%
Intel x86: 1.7%
I think a lot of the Intel stuff has been discontinued, not sure what is actively being developed outside of ARM right now.