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.
I don't agree with your first sentence: in many countries sports betting has been legal only for the last few years, even in the ones with the greatest tradition like what happens with football in LATAM. Of course there was illegal betting in the past when it was forbidden, but I din't think it can be compared to the figures of today when people can bet hassle-free. So sports betting could've started about the same time, but evolved at a different pace in many places.
Yea, you are correct but I was not actually referring to when it started in some countries or when it became hassle free, I mean when did sports betting actually started, it dates back from 800 to 700 BC, that's what I mean about when it started. I know some countries didn't endorse it yet until later but my country starts sports betting far back in 1920s and there's no body that thought about match fixing then. I also agree with what you said about the rise in illegal betting now compared to before.