That's an opinion, not fact. The charter of such an organization or co-op could be written to that effect, and in fact, Uber and Lyft could refuse to do business with employers that didn't support that structure. My point isn't that employees are immune to being screwed over in such a structure, my point is that they do not have to be which is what the parent post was suggesting.
But they do have to be, otherwise they would go out of business. If someone can choose when and where to work and they choose a time and place where people mostly don't need rides, they mostly don't do any work or make any money. Which they may be fine with if they're willing to be signed in for 40 hours a week but only work 10.
If you force them to a fixed hourly wage, you can't hire that person and still let them work those hours in those places, because you'd be paying them for 40 hours while they're still only working 10. So the now money-losing employee either gets a pink slip or has to work different hours.
A fixed hourly wage is not mandated by this rule, a minimum wage is. So you do this, ready? Everyone continues to drive exactly the way they do right now. All revenues go into one big bank account.
Next, you provide incentive payments for drivers proportional to the extra amount they brought in above and beyond the minimum wage for the hours they drove, as a slice of the pool of revenues after subtracting out minimum wages and benefits. Then you stack rank your drivers at the end of each half, and fire the bottom 20%.
I'm not even advocating this approach, I'm just saying there are ways of incentivizing this that are shown to work. This part here isn't rocket science.