Microsoft had over 90% market share at the time they used their free, and really crappy, IE to pretty much destroy all other browser developers.
It's not anti-trust unless it hurts consumers. Being forced to develop on Apple software/hardware affects consumers not at all. What harm is resulting from being forced to use a webkit browser? Being able to load only apps vetted by Apple would also be difficult to show harm given all the malware that keeps popping up on Android.
Apple is only 38% market share, Google is ~60%, it's right in the article. World wide Apple is only 18%.
I know people hate Apple but really, can we stick to hating them for the crap they actually do.