There are a lot of comments along the lines of "why are the fines so low" or "why is nobody doing jail time?" And the answer to both those questions is: stiffer punishment would require stronger proof. Cartel activity, like much white collar crime in general, is extremely difficult to prosecute, because the difference between totally legal conduct and illegal conduct comes down to what people are thinking. Instead of being able to point to a huge stash of drugs, cases come down to the fine points of "who knew what when" and "who talked to who and about what."
To impose punitive fines or jail time, you need to bring criminal actions where you need to prove beyond reasonable doubt cases where the proof is in peoples' heads. Civil fines, on the other hand, have a much lower burden of proof: more likely than not.[1] That's why civil penalties and deferred prosecution agreements,[2] have become the tool of choice for regulators.
Frankly, you don't really want to live in a world where the government can impose criminal penalties on businesses for such loose facts as these. Understandably, banks aren't the most sympathetic defendants, but extrapolate this reasoning to the tech industry. Should Bill Gates be in jail for his role in the Microsoft antitrust activity? Should Eric Schmidt be in jail for his role in the employee wage suppression collusion?
[1] This description is America centric but the operative law is roughly similar in Europe.
[2] A deferred prosecution agreement is a settlement where a company pays a fine, agrees not to do whatever bad thing it did, usually agrees to some number of years of monitoring, in return for which the government defers charges and eventually drops them if the monitoring period ends without incident.