Chalk it up to the RNG - I’ve had games where they were every where (20+ by summer time with 14 days seasons) and games where I hadn’t found any by the end of winter.
Also, I’ve never found either kind of ID card at the same place as the corpses with lots of drugs… there are distinct “batches of corpses” types: military, science, druggie, athlete, camper/outdoors-y types, etc.
Not much else to say, really, except to keep looking… or develop other ways to get in (jackhammer is the easiest, just make sure the turrets don’t annihilate you)