That's the point. Except with some attempts back in the mid 90s, Apple hasn't licensed their software and have instead done a vertical integration of their products and are selling a product.

Tangent to this is that Safari isn't the dominant market browser in any space.

    * Mobile worldwide https://gs.statcounter.com/browser-market-share/mobile/worldwide
    * Desktop worldwide https://gs.statcounter.com/browser-market-share/desktop/worldwide
    * Mobile US https://gs.statcounter.com/browser-market-share/mobile/united-states-of-america
    * Desktop US https://gs.statcounter.com/browser-market-share/desktop/united-states-of-america

One can't say that Apple's bundling of Safari within iOS is letting them abuse their market dominant position to force other companies to install software that they don't want to.