Sports betting and sports activity started about the same time, so it has always been a thing that ran along together, it's just now that the system is beginning to get corrupt and leading to match fixing, else for the decades that sports betting starts, there was no record of match fixing. The major advantage of sports betting and bettors reign praises on is the possibility that they are able to double their money from it, though it's not guaranteed but it still favours many people.
Not on major sports you can discover this uncalled attitude of match fixing, am not saying it does not exist, but it all depends on the sport category in consideration and the kind of league in question as well, sporting activity to also contribute in respect to sport bet have a long time difference or margin to be specific, because people have been playing sports right from time and also do gambling activities on different sports exist, before majority of the people now believe they could actually have more interest on playing sport bets than other games in gambling.