I think it is really simple. I don't think it has anything to do with power efficiency. If anything resemble notable cause, then Apple simply wanted to be the s

I think it is really simple. I don't think it has anything to do with power efficiency. If anything resemble notable cause, then Apple simply wanted to be the sole API provider. Apple doesn't want Mozilla / Microsoft / Google / Opera etc implement their own browser engine and demand or even dictate Apple's iOS implementation roadmap. It's better off the have the full control of what developers can do on iOS.