-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.