>But most mobile web browsing worldwide is from Android devices
Of course it is -- there are way more of those Android units.
But I wanted to point which users are more active, not mere volume. Even in the US Android could have more volume, but iOS users still generate far more traffic (not as total: as traffic per head).
If the 10% or 5% iOS users in a country generate the 20% or 30% of web traffic, then they are much more heavier tech/web users than the others.
Apple does reap the lion's share of profit from smartphone sales, but they don't dominate smartphone use.