Let's face it - no one really buys a Jeep for fuel economy. The vehicle's design doesn't really allow for that, nor does the addition of many great aftermarket products. That's why engineers went to great lengths to address the issue for the 2018 JL Wrangler.
It is also why aftermarket products like throttle body spacers, programmers and tuners, and different types of air intakes exist. All in the name of giving that Wrangler added horsepower and additional fuel economy. Plus, for those who love to take their vehicle off pavement, accessories like a snorkel kit can help keep that engine cool during non-optimal conditions.