How do you tell there was no match fixing until recently? Modern football is about 160 years old, do you think this is the beginning of corruption in sports. We only get to know about corruption in sports because the victims were caught in the act, if they didn't find out the truth then maybe you might keep feeling like the game is without corruption. Match fixing has been a thing even in the past, it will always be a secrete among benefiters.
Match fixing is hard to figure out unless someone who's been involved and part of the circle will expose and becomes a witness of how it's being done.
And you're right, unless there are no people gets caught that are part of it. We will mostly think that they're clean games and no corruption involved and so as these match fixing isn't existing.
This is still happening but not to the major sports in the industry. Maybe in the smaller leagues where there's a connection from the major leagues but the sanctions are not that much so, they get involve.