In terms of the game indeed Serie A looks boring but from the boring game, gamblers can take a lot of profits because they always win bets. Why is that? Because various matches in Serie A are very easy to predict.
If you are talking about bets regarding Juventus I think that its a given but your statement isn't true for the whole Serie A league. Every year you will see 7-8 teams battle it out for the 2nd until the 4th spot and all of them only have 5-6 point differentials which is only 2 winning matches to catch up. If you are talking about game league predictability Serie A isn't one of them because I don't see how the rest of the teams has an edge on one another since they are pretty even in terms of competition.
After all, betting only for teams that have definitely won on paper, of course, will only have low odds and I don't think it will be interesting, because when it is wrong to predict it will be a very regrettable loss. Anyway, every match in each league must have the advantage that can be obtained for betting and all football teams in each league must have a period of increase and decrease each season which of course can be maintained by every good management.