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.

one more thing to mention about that default chrome on android: you cannot install ad-blocker there.

you may install firefox and still will have a lot of time links opened in built-in chrome, on android

The difference being that Apple has a huge percentage of the market share and Android isn't the only game in town.