And yeah, I think it’s unlikely someone could have made a more efficient browser than Apple since they didn’t give public access to all of their functionalities. And that might have been partly for security reasons, if there were less-secure aspects to hidden functions, for example.
The counter-argument is that they should have opened everything up, but Apple will say they were going as fast as they could responsibly go, and that’s why there were limitations that have been relaxed over time.