Maybe not ‘fixing’ a problem, but they certainly vastly improved on the service aspect of food delivery. Which is the aspect I care about.

Buy from places that have their own delivery service

Figuring out which local restaurant does and doesn’t currently deliver (which would change on a daily basis) was one of the main problems. Restaurant can still have their own delivery drivers but having a central place to look up who is currently (in-real time) delivering and what is a big improvement. Not going back from that.

Actually walk or drive or public transport to the restaurant and eat out

Brilliant. You can also cut down on commute/travel time and cost by just staying home. Or fix your depression by stop being sad! Big brain.