These are primarily people delivering food orders at lunch time for less than $10.
The people paying for these services will not pay what it would cost to have a “personal assistant”.
Also they can only deliver so many orders at a time. If all of your clients order lunch around the same time, it’s not possible to deliver in a reasonable amount of time.
most of the folks getting ubereats delivery are not the target demo for being a PA client. but you don't have to be super wealthy for the economics of it to work out.
most tech employees make enough that they could pay 10-15 hrs of low wage work every week to do stuff like pick up your laundry/groceries, pick up a food order that you've called in, take stuff to the post office, etc.
For food delivery, I imagine going back to pre-apps and have restaurant employed couriers for local takeout could be beneficial for both parties.