You can have a locked down and secure phone without a monopoly controlling your device. Apple is good at marketing security via security theater. Look at all the 0 days coming out. Hell the thing that probably embarrasses Apple the most about the Epic saga is that their justification for their 30% and not allowing sideloaded apps fell on its face when Epic's in app payment waltzed right through app review.

I have a hard time buying that the same users we struggle to convince to not use the same 7 character long password for every site care about security. They don't even know what sideloading means. They don't care about a secure experience, they care about the native experience. Ya click the blue icon with a white triangle and press Get on whatever catches your fancy.