"If I run an advertising agency and I've got 4 freelance film makers I regularly use and one of them stops taking my calls or almost always says no, I'll eventually stop calling him and add someone else to my regulars. It's just business, no point me wasting my time calling him."

But that's different than the situation with Uber/Lyft. In your story, the person has the ability to find new clients. If you're an Uber/Lyft driver, you can't exactly "go it alone", so to speak. You're kinda stuck with Uber/Lyft.

"I think there's a load of companies abusing the gig economy at the moment, but Uber aren't the worst and definitely not for things like they provide a GPS or set the rate, it's all the delivery companies and the gas-servicing people who all have to wear uniforms and work full days."

I disagree; I feel setting the price unilaterally is a huge part of why they're abusing things. By doing that, they are kind of dictating the wages that the driver can earn. If Uber/Lyft decide to change the per mile rate, there's nothing the driver can do. By contrast, something like Angie's List allows the different providers to set their own rates.