In finance technology is seen as a cost center, not a profit center. They want the minimum needed to ship. Early on this results in a lot of tech debt. Later on, fixing the system is too hard and thus they need to hire super smart people to figure out the mess they are in for any code change.
Enforcement actions are INCREDIBLY rare. The penalties are shockingly low. Thus the cost of failure to comply is low, and the businesses are not prioritizing compliance.
If enforcement actions are rare, it's probably because these firms are playing clean for the most part, contrary to popular belief. If you trade 5-10% of the market, regulators are going to audit you every year. They are looking for even the smallest issues to give a fine, even minor things like not having the right Head Trader's name on your supervisory forms after someone quits.
I've seen this at countless finance companies, and from interviewing people across the entire spectrum of finance. It is a rare corner of the industry where you'll find quality engineering. Usually everyone in a finance company thinks they are amazing engineers, and are just plain wrong.
My advice: work smarter, not harder.