Not only with sportsgambling but to all gambling games. Reason? Winning is never certain therefore playing more often would expose you to higher risk. Even if you happened to won big, it'll eventually be turned into loss; you won't win always. Higher exposure means higher risk unless you are lucky enough. Analysis would work indeed in sportsbetting but as we all know, anything could happen within a match. Even underdogs has chances to win and if you would be too greedy of winning because you have a lowe odd bet, then be prepared to suffer big time as well once the unexpected happens. We are all prone to greed and frustration.
Sport is a physical game and for this two teams play physically on the field so here it is easy for a stronger team to win the match but sometimes it is seen that the stronger team unfortunately also loses. one who knows more about the team and better about the player's performance can predict the outcome of the match successfully. But this prediction does not always work because many times it is seen that many good teams lose easy matches then many professional gamblers also lose there bet