I live in an apartment so I can't take the camper off when not using it. Also, it's my daily driver and stays on year-round thus - YES...fuel economy is a concern for me. Even if it's just a couple extra MPGs lost like the above example that would be $70/month at just 1000 miles.
I consider myself, generally, a pretty 'happy' person. I have a job I love and take trips with my pop-up camper on my Tacoma whenever I can(I have over 50k miles in just 2.5 years ownership). I don't think it's unreasonable to at least THINK about fuel economy. Did I consider how a hard-side camper would look on my Taco? You bet, but if it can also save me money(not just at the pump, but in initial purchase price)...
I drive like a grandpa anyways and won't put AT tires on just for that 1% of the time I'm on gravel or dirt. I have easily averaged over 20 MPG with this set-up even though it makes me a miserable, sad person