Yeah but Google isnt Apple and yet they have Maps that gets updated with each firmware. Youtube isnt apple and they have control over that. How do you know they wont work with Mozilla to make a Firefox app that they can control with updates, etc..?
Maps and Youtube and things Apple doesn't have in-house. They decided they needed them and found a place to get them.
Why would Apple need another web browser? Name a reason you like those browsers better and they'll say "we can make Safari do that." I mean, answer why Apple (not you) would want another browser to compete with their own.
I can't think of a reason. It's not impossible, but no reason = not likely.