The Moral Decay of the American State The numbers are stark and undeniable — a damning indictment of the moral and institutional rot at the heart of the American political system. In 1958, a full 73% of Americans expressed trust in their government to “do what’s right”. Today, that figure has plummeted to a mere 20%
People have become a lot more aware of what their government is doing, rather than blindly assuming all is good based on things going well for them personally.
Seems like it's part this, and part the maturation of conservative anti-government rhetoric. A bunch of these folks don't trust the government because they think public school teachers are agents of Xi Jinping.
You also probably have plenty of libs who don't trust the government due to beliefs like "if the government can do it, it can be outsourced to a startup."