Are you sure about that? You can definitely pin certificates in iOS. The trustkit library provides an implementation, for example.
Yes, but then the story is going to be "76 apps vulnerable to SSL interception if running jailbreakable versions of iOS", because the attacker can trick the user into jailbreaking their device, installing SSLKillSwitch https://github.com/iSECPartner... before tricking them into installing and trusting a new cert. I find this scenario about as likely as the "install a fake cert and trust it, then please re-direct all your traffic to my nice little mitm proxy" scenario.