Does our system have something they want?
Who knows what they want? Perhaps some other system has more of what they want, so it is more profitable for them to go there than to go here. I can't imagine that interstellar travel would be cheap. It's a major failing of Star Trek - where did the Federation get the money to pay for all of that stuff?
Besides that, the ability to travel faster than light implies the ability to control light. If Captain Korg of the Klingon Empire was tooling around Venus and Juputer, we would never know about it.
It is assumed but rarely shown, that there must be a larger, commercial infrastructure supporting the Federation. However, except on rare occasions, Captain Kirk and whoever might be the equivalent of Bill Gates don't travel in the same circles. He usuually runs into the smaller operators.