Here are two claims which both seem true to me:
1. The empirical evidence on generalized social trust, including trust in government and institutions, shows that it's generally a very good thing if people have a high degree of trust in each other and their institutions. It makes them behave better, free ride less, cheat less, and so on.
2. Many prominent US institutions are not trustworthy. Most media is heavily biased and has an agenda other than promoting the truth. Government does some good things, but does lots of very bad or dumb things for self-serving reasons. It frequently caters to voters' irrationality. Our universities are mostly run by selfish people for their own private benefit. Other Americans are fairly lousy people, morally speaking, and are highly biased and tribalistic. Looking around, it seems sensible not to repose trust in many of our institutions or in others.
In short, it would be good, in certain respects, if people trusted each other and their institutions more. But, at the same time, lots of people and many institutions are not very trustworthy. It can be dangerous to repose trust in people and institutions which don't deserve it.
If you wanted to fix the US, where do you start? Do you want people to repose more trust in these in fact untrustworthy institutions and people? (Maybe they are untrustworthy but people repose even less trust than they should. Perhaps the NY Times deserves "trust level 4.58" but the average Republican incorrectly reposes trust level 2.33.) Will trusting the untrustworthy induce them to become more trustworthy?
Or do you start by fixing the incentive structures which lead people and institutions to be untrustworthy? But, then, isn't one of the problems with reformers and critics that when they come around to fix things, they induce others to reduce their trust, because they demonstrate how untrustworthy the institutions are? (For example, Cracks in the Ivory Tower should lower your trust in universities, while Injustice for All should lower your trust in the criminal justice system.)