So the family and the neighbors are clueless and unable to defend themselves while this drug addict breaks windows to break into their houses, steals them blind and takes things to get pawned. I assume the drug addict does not have a job.
I don't mean to be rude but either your story is untrue or your family and neighbors are incredibly naive. If everyone in the world was as naive as your family and your neighbors then maybe your theory would bear scrutiny. Most people would have figured this out much sooner and would have had him arrested.
And he was a thief before he was a junky, takes money to get a drug habit. Certainly a big chunk of it was the family not taking the raising of him seriously and kicking him out of the house.
How are the neighbors supposed to know? They go to work, they live their life, one day they go into the storage shed and stuff they could have sworn was there isn’t. They don’t know when it disappeared, and they don’t know who took it. House “cleanings” are pretty rare, though they’ll happen, mostly it’s about grabbing enough stuff for one fix and getting out. Of course even when they do “clean” a house it’s a basic suburban neighborhood, there’s thousands of other houses within walking distance, and a “cleaned” house can provide enough dope for months.
You’re living in the land of theory, out here in the land of reality you’ll NEVER price junkies out of the market.