You're forgetting the power a discontent population can have on government. In case all browsers took a stance against cooperating with silent MITM, this would

You're forgetting the power a discontent population can have on government. In case all browsers took a stance against cooperating with silent MITM, this would be a great pressure on powerful entities not to do it. Governments can get away with suppressing people's online experience for a while, but if they have subpar experience and basic websites won't function properly due to dated browsers, the pressure on governments to get modern browsers may increase.