In a larger department, you have teams of specialists. A young patrol officer may be the first responder, but soon after that the detective, forensic, or traffic units take over. These officers have a special skill set to handle it beyond the first-arriving patrol officers, who pass off the workload and go to the next call. These officers have great exposure to a wide variety of calls. One year in a large metro department will expose you to several years' worth of experience in a smaller town.
The International Association of Police Chiefs draws the distinctions for smaller agencies at 50,000 residents served, medium agencies at 50,000 to 500,000 residents, and large agencies at greater than 500,000 residents.
A smaller- to medium-sized department is a much different organization than a large agency. The smaller-town first responding officer follows a case from patrol to prosecution. They gather evidence, prepare warrants, perform interviews, and present it to the district attorney. It's their case from 911 call to courtroom.
This can create a feeling of becoming a generalist rather than a specialist, yet their skill sets must be at a higher level. Training this department requires more insight than most expect.
The smaller-sized agency must develop in-house support. Some officers may develop enhanced skills and expertise, but they lack a rapid response support staff. This also creates the opening for regional or county-wide teams to help with a mutual-aid response.