Very true.
I once had to track down a hit-and-run driver myself, because the police didn't have time for it.
After finding the vehicle and passing along all available information and some 1-hour photos that I had developed, the officer in charge of the case reaffirmed: "If you hadn't found [the driver and owner], they would have gotten the vehicle fixed and eliminated all of the evidence before we ran across them**. We just don't have enough time for stuff like this..."
**(Aside from the time afforded to the suspect(s) by typical delays in finding a hit-and-run driver, the owner of the car worked at a collision repair shop.
)