I’ve read that the FCC will actively pursue reports of pirate stations or other illegal interference, and they’ll drive around the neighborhood in a van to triangulate the offenders.
In fact here’s a list, but it looks like they stopped updating in 2018.
The FCC does do enforcement, its just that much of is is reactive based on complaints from other spectrum users. They aren't rolling around making sure that, for example, a license holder licensed for 10W isn't operating at 15W by using a higher gain antenna than originally specified. Those are the sort of violations that are reasonably common, but also are unlikely to impact other users significantly, so generally wont be complained about.
In fact here’s a list, but it looks like they stopped updating in 2018.
https://transition.fcc.gov/eb/AmateurActions/Welcome.html