In a country where tipping of 20% is the norm ... there is all of sudden a cap of 10% on what the delivery guy can make?
You can still tip the delivery person as much as you like.
Since all these services are operating at the loss, the "delivery worker" might actually get more than the full fee.
But in any case, my point is that the cap is not on how much that person can make, but on how much these companies can charge.