I don't thing that's an accurate description. Sure, Bkb Odenkirk was incompetent, but the first sherrif in the first season wasn't (and wasn't he grooming Molly as his replacement, his untimely death being the only reason Bob got the job?), Molly's dad was good at his job, and the new sherrif in season three didn't do much seem incompetent as it seemed like he was playing politics and just wanted the case closed, regardless of the truth. That makes him a bad Sheriff, but not necessarily an incompetent one. He'd been running another police service well enough that the city/town/municipality decided they wanted to merge police services with his and put him in charge at any rate, that speaks of some level of success and competence.