The problem is the delivery companies are abusing the definition of “tip” and how they pay their drivers. I used to drive deliveries for DoorDash and they typically only pay $1.50-2.50 per delivery, despite charging $6-8 for a delivery fee, on top of prices typically being 30% higher than the menu in the restaurant. As a driver, the rule of thumb is typically that you shouldn’t take a job paying less than $1/mile. So the rest of the money for the driver comes from the “tip”. A tip is supposed to be a bonus reward for good service, but the reality of the situation on these delivery services is that it’s just the rest of the delivery fee to the driver. The delivery companies know if they list it as an actual delivery fee they’ll lose customers because some customers will feel like the fees become too excessive. So instead they exploit inexperienced drivers into taking orders thinking they’ll get a tip later, but often end up with nothing. And customers who think the tip is actually a tip according to the original definition and voluntary often end up with bad service because experienced drivers will pass on the deliveries, meaning they sit and sit, with food getting cold while the delivery service eventually starts offering to increase the pay in 25¢ increments after a certain number of rejections. Sometimes orders will sit for a couple hours before someone will finally take the order. This is still bad for the drivers, because the customers will often leave them a bad review, blaming the driver for the order taking so long to arrive. The driver doesn’t know what part is “tip” until the delivery is complete.

The reviews are another bad system. Historically people think of a 5-star rating system goes from 1 star being terrible, two being below average, three being average, four being above average, and five being excellent. However, rating systems often rank anything below five stars as bad. So people will leave a four star review thinking that’s good but as far as the company is concerned is bad. IIRC DoorDash drops any driver with a rating below 4.7. And we see this problem a lot of places online: product reviews on shops, online business reviews, even hotels where 3 stars was traditionally decent now see that as bad.