[nl]

Which factors exactly on ARM's side?

I can think of only two:

1) Power usage on low end chips. ARM will be ahead of x86 on platforms below the smartphone for the foreseeable future, and on smartphones for another generation (2-3 years)

2) Manufactures can customize ARM to build SOCs. I can't see Intel allowing complete customization like that, but I'd expect them to ship some competitive SOCs themselves.

[rbanffy]

It's simpler for ARM to adopt performance enhancements that make the core more complex than for Intel to adopt simplifications that make their cores more power efficient without losing performance.