In Rose’s day, you could only bet on who won and how many runs. You also needed a bookie to take the bet.
Now you are able to bet on just about anything in game or with a specific player. You can literally live bet if someone is going to get a hit while they are at the plate. It’s gotten nuts.
This gives so many options for a few bad actors to try to fix a bet. They don’t even have to influence the outcome of a game anymore. It could be one at bat, or pitcher strikeout, or a first inning run. It leaves almost everyone as a possible fixer. It could be a fringe player, base coach, bullpen catcher, or umpire using either advanced knowledge or even doing something minor during the game to rig a bet.
This is a dangerous territory for MLB and the only way to protect themselves is to keep these very strict and harsh punishments for gambling.