After all roaming monsters had been dealt with, humanity was finally able to focus on the true long-lasting threat, the Gates that spat them out.
It had already been tested that clearing a Gate of monsters results in its erasure. Unfortunately, as much as it made sense to concentrate on clearing the sources as the number one priority, it just wasn't feasible at the time.
Years later, however, everyone was racing to capitalize on the value of Gates. It was no longer a matter of life and death, it was all about profit.
While the Enigma Stones had long failed the test as an energy resource, the Ability Users that they created didn't. As long as you hit the jackpot with your ability, much more than simple energy could be created.
The biggest example of using abilities to advance society were Ability Measurement Devices. Through the group work of some special Ability Users, they managed to create a machine that could measure and identify the abilities of others!