Sure, if you are hiring one person to do two jobs, it is going to be a struggle. Even two jobs that are related to each other - if they have different skill sets, it is two different roles.

Take racing as an example. Drivers and mechanics are clearly related and both critical to success. And most drivers can handle some mechanic work, while most mechanics can drive. But you don't have one person doing both roles on race day.

Hiring one person to do two jobs increases the time to the finish line. You same some money, but you come in last.