Like in real life, you could absolutely choose to always go to the one expensive shop you trust rather than a cheap one in a dodgy street.
Wishing for the shop you like to have and use the power to remove the other ones from existence has nothing to do with your own security.
there is no reason you couldn't have this while also having competing app stores. All you would need to do is not install the competing app stores.
Same way people blamed Microsoft when Bonzi Buddy made their computer barf.
Right now the perception of iPhones is that they work. Soon as people are tricked (and given the $$$ at stake that will happen) into installing malware infested garbage, the platform's rep will take a hit.
Android used to allow apps a lot more freedom, but then android phones turned into ad filled monstrosities with a battery life measured in fractions of a day, and Google had to clamp down.
I'm happy to have my house in Apple's gated community because I know every day I'll drive out to Linuxville at the edge of town and work in my shop filled with sharp tools.