I think it would be much faster to do this by patch rather than by turtle, since each turtle on a patch seems to be calculating the same value of wealth. Perhaps something like:
ask patches [
let my-turtles turtles-here
if any? my-turtles [
let w Storage / count my-turtles
ask my-turtles [set wealth w + food_carrying]
]
]
]
If you kept a running set of patches with turtle homes you could just ask that subset and not have to worry about there not being any on the patch and getting a division by zero.