Don't most iOS bugs these days require multiple security exploits in order to work? I'm not sure it's always that simple to find a reliable exploit just based o

Don't most iOS bugs these days require multiple security exploits in order to work? I'm not sure it's always that simple to find a reliable exploit just based on what code has changed (because lots of code has changed). If there is an obvious to find, easily-exploitable bug, the update could be pushed to everyone (the way updates are pushed today). There is a balance to strike here. If issues with auto update cause enough people turn auto update off, I'm not sure it's helping security. Finally - Apple already has a beta programs including public betas. Are those binaries not already used to find exploits? Essentially, I'm not convinced a phased update (with public security disclosure slightly later) would lead to worse security than we have today.