You can, but by default you get Chrome, which is about the same thing people were fighting Microsoft over in the Netscape-IE days, but this time on Android.
That case created a misconception that refuses to die... There's nothing inherently illegal about having a default app or product. There's also nothing inherently illegal about having a popular app or product.
The reason Microsoft got in trouble is because it was not only found that they had a monopoly in a particular market, but that they obtained some of that market share illegally through shady contracts effectively forbidding OEMs from offering alternative OSes, etc... They were then found to have used that illegally obtained monopoly to take over a completely different market in part by bundling IE with Windows and punishing OEMs who sought to including alternate browsers and completely disallowing the removal of IE.
"Huge"? In the EU, where the current investigations are going, Apple is barely a blip on the radar. Windows Mobile has had better traction in some parts of Europe than the iPhone.
Android has over an 85% global market share. And for OEMs, there is NO other game in town, since iOS isn't licensable.
The reason Microsoft got in trouble is because it was not only found that they had a monopoly in a particular market, but that they obtained some of that market share illegally through shady contracts effectively forbidding OEMs from offering alternative OSes, etc... They were then found to have used that illegally obtained monopoly to take over a completely different market in part by bundling IE with Windows and punishing OEMs who sought to including alternate browsers and completely disallowing the removal of IE.