. . . it may be that there is a bunch of low-hanging fruit hiding just around the corner.

I would stay in the fruit tree metaphor and say they might be "hanging right over our heads".

Gee, that was obviously supposed to be a non-mixed metaphor about urban foraging. Yeah that's it. :)

Seriously, I thought about sticking with the fruit tree metaphor, but "hanging right over our heads" makes the problem sound too easy, so I decided to favor accuracy over literary elegance.