One toilet is good for a crew of 10 for a week. A single porta potty in an urban setting may need cleanout daily. They aren’t always cleaned up on site, sometimes pulled and replaced to clean up at the yard.
I rented some over the summer. To send a cleanout truck midweek was $50. I think the cost to rent 5 of them was about $400
They might find that placing multiple units at the same site is almost the same cost.
The contract calls for twice daily cleaning, and refreshing the fluids, apparently soap and some water. I assume they must have hand towels as well.