I am aware that Apple allows other vendors to wrap their browsers around a Safari component on iOS, but they do not allow them to use their own rendering engines.
Firstly, why do they do this? And secondly, does this violate antitrust laws in a similar way that Microsoft did with IE?
The issue with IE was that Microsoft was using its monopoly in the operating system market to unfairly drive out competition in the browser market.[1] Apple, on the other hand, has only 45% of the smartphone market in the U.S. today,[2] so nobody has a monopoly in that market.
[1] https://en.wikipedia.org/wiki/United_States_v._Microsoft_Cor....
[2] https://macdailynews.com/2019/03/13/apple-grows-iphone-marke...