There are. I live just outside police jurisdiction. My neighbor got his truck stolen and called the police, they said "Sorry, can't help ya, call the sheriff." He called the sheriff's office and got a recording that they are only open Wed-Thurs-Fri, 12pm to 4pm, that he could leave a message and expect to hear back then (it was Saturday).
He had video of the thieves and the car they showed up in, including license plate and clear shots of their faces. Sheriff said "Well, it's been five days, they probably ditched that car by now, not much we can do."
Sherrifs are complicated. First it is important to understand that police are tied to the cities they serve in. There are parts of cities are are not incorporated and thus need a different sort of law enforcement. Mostly remote places. But it does happen in denser areas.
Sherrifs are elected law enforcement. You can "run" for sherrif and just be some rich guy looking to play cops and robbers. See Texas.
However there are sherrifs officers that are on the same wavelength of police and just to enforce where the lines keep the police out. And you might think "Well why don't they just incorporate the parts into the city?". Lots of other issues with how the land is distributed in other ways.
Well, odd how these officials were supposedly elected by a population that leans Democratic but they are almost exclusively Republican, 90% white and 97% male. There is something about the position (I think historical connotations) that make it disproportionately attract/favor white conservative men.