I was told with anything under $500 I would have a Private Eye to do the initial "investigation".
Sounds to me like you were blown off. The correct answer would have been, "we have no man power to aggressively pursue these small thefts". Unless its just a slam dunk that is. The under/over $500 thing is just for case reporting. "Under" gets a code and "over" gets a different code. But in general the more valuable a thing you lost the more the Police will look for it. Which pretty much means unless you lost the Mona Lisa you just bought for 100 m then forget about ever seeing it again.
But even that depends on where you live. If you live in a small town the detective may actually take the time to investigate. In the big city nobody really even investigates stolen cars unless some kind of pattern emerges. The car gets inputted into LEADS and NCIC and then we wait to find it in some ways. Oh your case will get assigned a dick but that report will get stacked with the thousand other ones on his desk. And who knows? Your agency might actually have a policy to not even bother with under $500's, or as we call them "0820's". Maybe to not even call back the victim
No doubt many are thinking "Lazy Cops" cause they have been programmed to do so. But the real problem is there is so much thieving committed by a small % of repeat offenders, who get so many "get out of jail cards", and they make it so hard to prosecute them and put them into prison, that the entire thing has become a joke. And every one of the thousands of thieves Ive caught in the last 3+ decades have all stolen for exactly one reason. To get high. People dont steal to feed their kids in America.
But if you knew where the item was, at another job sight, and could prove it, then Im surprised more action was taken immediately. At the very least you should have been told how to pursue a warrant on the guy. But if you could prove it was there, that it belonged to you, and it actually WAS there, then the guy should have been arrested on the spot.
Let me guess? Power tools right? Man dont ever let power tools out of your sight. A Junkie will have them sold and shot up their veins so fast your head would spin.