This is the future for iOS once sideloading comes, and many iOS users will not be ready.
No, how long have Macs been around? And how long have Mac users been able to get their apps from any source? And how devastating has that flexility been for the majority of Mac people?
Yes, there are cases but relatively few and far between. The App Store is not immune either- occasionally a nefarious app gets through and affects users who downloaded that app. Windows runs on far more computers and has far more viruses/trojans/malware (and far more bad guys trying their best to do this kind of thing there) and yet there are not really that many cases where someone's life is destroyed even in that Windows world due to this sort of thing.
We don't need "security" to scare the masses into embracing a monopoly scenario of buying from one and only one source. No consumer wins when all competition for their business is reduced down to a single seller. I cannot recall any situation in all of history where a single seller does not exploit their exclusive position... until competition shows up and drives down pricing for the
same products or services.
Consumers simply need to be smart and make good decisions about who they trust. Will even the smart ones get that wrong sometimes? YES. Does even Apple let a bad app in the App store sometimes? YES.
But no need to cede competitive marketplaces to single sellers out of this type of fear. Anyone that afraid can already embrace getting their apps from the divine, one and only. Everyone else should prefer to hang on to the great power of consumer flexility to shop around and choose for themselves vs. trust one- and only one- seller. There is no consumer win in that scenario... only an illusion of one... much like the illusion that the whole world will be destroyed once people can choose to get apps for their iDevices from sources other than Apple. We've had periods where that has been possible too (jailbreaking) and there was never any story where all who dared buy elsewhere suffered devastation, fire & brimstone.
Again, anyone too afraid to shop from other stores, won't have to do so. They can maintain their illusion of security by continuing to buy from only Apple. However, others may prefer some genuine Capitalism competition, the concept of more of the money we pay potentially reaching those who create what we buy, AND the flexibility to have apps that Apple refuses to allow for any old reason (not always an actual good reason).
IMO: just as we are with Mac apps, we will be better off when there is more than one seller of iDevice apps. And just as we experience with our Macs, the odds in the impending doom & destruction spun by that potential seems farrrrrrrrr overblown. We
already know this because our Macs are loaded with the same keychain, the same private information, etc. We simply pretend that it will be different with iDevices for some reason. Why? Mostly because Apple says so. Why? Because there is a LOT of easy revenue in Apple's cut of every single sale in the one and only iDevice store. No exclusive seller of anything EVER wants competition... and will say & do ANYTHING to try to maintain their lock on that easy money.