This is less complicated than you think.
In the past you'd sit at home and think, "I'd really like a hamburger from Joe's Burger 3 miles away, but I don't feel like turning off the Celtics game and getting in my car to go pick it up. Too bad Joe's doesn't deliver."
Now Joe's doesn't need to have a constant delivery demand in order to contract with a service which delivers for them.
And John Smith, who has a vehicle but not a lot of decent job prospects, would rather drive burgers and other food items around town for different restaurants if it means he can be his own boss, select his own hours, and still pull down about the same money after tips as he would at a rigid, repetitive, soul-crushing service job.
This all seems like a win-win-win for all involved, until you start to consider the various possible downsides to a lot of this -- the lack of accountability/consistency of service, the dead-end subsistence type living, the unsustainable business structure of the parent gig company -- to where we haven't really found the magic bullet we think we've found.
But this was all inevitable with the growth of app-based convenience services we've seen this decade. It's not a referendum on the economy. It's simply a new form of business and temporary employment trying itself out. Time will tell what eventually happens.
On a side note, I don't use any of this crap. I like doing things for myself. I'll pick up my own food, drive myself places, and run my own errands. But I do see the appeal if you're one who values convenience over control.