There are amplifiers that increase the suck. One is physician ownership of diagnostic clinic(s). A strong tendency to order tests can be remarkably enriching, way more than a paltry $500K.
There's also rules regarding things like percentage ownership of physician owned facilities and the percentage of referrals to that equipment that come from the physician owners.
Urine drug screens in an in-office "lab" are another big source of revenue for certain specialties that involve referring patients to your own tests, or doing your own pathology on biopsies as a dermatologist or whatever. My understanding is that most of those things, and many like them, are not Stark law violations.