Browser vendors have an incentive to maintain trust, it's their stock in trade. If they screw up, it directly affects their bottom line because people will move elsewhere. Their goals align closely with my own.

A foreign government (or even my own) has somewhere between zero and weak alignment with my goals. There's little reason they would want to choose good certificate authorities and strong reasons why they would choose ones their intelligence agencies can backdoor. Why should I add them to the chain of trust?