-Is there a possibility that spectators of a sport like you and i with no professional training can develop a better understanding of a sport than some professional coaches of some teams?
Yes, it's possible, but often it's just because of asymmetric information. Pundit only looks at the match day performance, and not measuring progress, fitness level, and training performance. Often the coach sees Player A is in a good physical shape, training well, seems can be trusted. But on D-Day, he plays like a crap. Thus Pundit questioned the coach judgment instead of other things, like Player A choked. Conversely, Player B is a troublemaker (not discipline), not training well, and prone to injury, but he often plays well on D-Day. Thus, fans and Pundit think he is a better player and should be played more where it can be just a fluke.
Speaking of tactics, the team needs to understand and execute tactics correctly before it can be deployed in a real match. Often, pundits are just like "why not use tactics X or Y?" when the coach already tried it but failed in training.
What you say makes sense...
Have anyone ever heard of Dunning Kruger effect? This effect shows the more uneducated, clueless people are about something, more confident they become that they have the perfect solution for that, because they see everything in a very plain, simplistic way. I think I could relate it to spectators who imagine they are more capable than teams' coaches, while in fact they don't know anything, because they don't participate the daily life of the team, trainings and preparations for the games. So I don't think spectators know better.