For any specific improvement in quality of life, as it is commonly understood (and whether it's measured for an average person/median person/the most miserable person/...) there's very obviously somebody who doesn't contribute to it. Not literally everyone helps run a homeless shelter, plant a forest, build a highway, or run a non-corrupt judiciary. Similarly, there are quite obviously some people who detract from any particular improvement, either directly (whether it's a corrupt cop decreasing public trust, a burglar decreasing safety, a factory fouling up the air, a hiker littering in the park), or by using up a public resource more than they contribute to it.

There's no reason why somebody's combined contribution cannot be a net negative. So, it's very easy to find such a person.