Having done Doordash/Ubereats in the past myself that is ABSOUTELY not the norm, god I wish it was that streamlined. Picking up a single order and delivering it straight to the customer is by far and away the most common scenario for the drivers.
They do have stacked orders which are the multiple pickups you're talking about, but I've never had more than 3 orders "stacked" together, and I would say it's more common to have stacked orders from multiple different restaurants rather than multiple orders from the same restaurant. And from the driver point of view stacks suck because almost always only one order in the stack will have a tip, the others will be no-tip orders they couldn't get someone else to deliver by themselves.
Doordash also recently changed how they pay out on these stacked orders to the drivers detriment. It used to be you'd get the base rate for each order in the stack, so 3 orders stacked together would be the base rate x 3 + whatever tips by each customer, but now they pay them out as one big order no matter how many orders are stacked together, so you get a single count of the base rate even if you're delivering two or more orders in a stack, which again are usually only a single order with a tip, so you're effectively delivering the other orders for free.