The SEC is on the hook to investigate anything reported to them. If they aren't investigating, then it's not being reported. Additionally, there is an incentive

The SEC is on the hook to investigate anything reported to them. If they aren't investigating, then it's not being reported. Additionally, there is an incentive to report shady behavior(such as wash sales to lower price, as you described): https://www.sec.gov/whistleblower https://www.sec.gov/whistleblower tldr; the SEC pays you a portion of any fine they levy against an entity.