Who's to say that this isn't happening in the US as well? The US has invested billions of dollars in dragnet surveillance that is allegedly useless for anything other than metadata in the context of HTTPS.
Is it out of the question to ask whether our secret courts could issue gag orders and claim that national security mandates CA root keys? Such a gag order would only be served to a small group of engineers at large companies, and those engineers would have no right to report on it. We're talking about only a few hundred FISA gag orders, and thousands are served annually. It would make their multibillion dollar infrastructure useful again, wouldn't surprise me if some (unnamed, anonymous) judge bought the argument.
To employees at vulnerable companies, what's your PKI like? Is anyone aware of a company that implements strong multi-party checks on accesses to important private keys? If the NSA wanted your keys, how many employees would need to be served gag orders? Is it on the order of dozens or hundreds?