Earlier quoted context omitted.
Unless you are a slave, abolishing slavery would only cause you to face higher prices ...
No one is forcing them to do this work. They opt-in to being a driver. Slavery is coerced labor, how can you even make the comparison?
There are different levels of coercion. After all, even a literal slave doesn't have to work -- they can just allow themselves to be beaten to death. But given the choice between being beaten to death and working, most people choose working.
But the fact is that even people who aren't slaves still have to have a place to live and something to eat. In the 1800's, lots of white people in the North weren't legal slaves; but they were "wage slaves" in factories -- they worked 11 hours a day, 7 days a week, for just enough to have a roof over their head and food in their stomachs; and if they got sick or injured they were just out of luck.
The idea that all of those people were "opting in" to that kind of life is preposterous. They were being coerced to work by their physical needs; and the Market, recognizing this, offered them the smallest amount better than "homeless and starving" that they could.
Obviously things are better now than they were in the 1800s, but only because we have laws against "opting in" to bad jobs. As soon as those laws are taken away, the Market will ensure things go back to the way they were.
Uber and Lyft have done many things differently than traditional taxi companies; but one of the things they've done is make an end-run round the labor laws that stop the Market from coercing people into dead-end jobs.
The only other way to prevent that kind of coersion is Universal Basic Income. If employees can walk away from a job that's dangerous and pays poorly, then the Market will make sure employers offer more reasonable conditions.