I am in no way an expert on this so please tell me if any of this is wrong...
As it stands now, the vast majority of cable/satellite subscribers don't watch or care about sports and they are subsidizing the massive media contracts that have been given out for years. To move to any sort of system where only the people who want to watch sports are paying for the service is going to massively reduce the revenue generated from subscribers. Which means prices are going to go up for subscribers and the teams and leagues are going to be making a whole lot less money than previously which will certainly cause the prices of tickets, merchandise, concessions, etc. to also go up.
Like I said, I'm no expert but this makes sense to me and I don't think it's good for MLB short or long term. It's already an expensive sport for youth to participate in and now it's going to become more expensive just to be a fan of. I feel over the past decade or so all forms of entertainment/hobbies/interests has become niche and therefore expensive, there are very few things that have widespread appeal anymore. The NFL I suppose but I feel most of their growth has been by those who are only interested in it for gambling and really couldn't care less about the players, teams, or game results outside of what it means to their bets.