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.
All factors, Windows compatibility excepted, are on ARM's side this time. Of course Intel has survived bad situations before, but this time I am not betting on them.