I recently took a ride in SF where I asked the driver if we could stock for fast food along the way (I had just had a 6 hour flight and I can't eat on planes for fear of motion sickness). He said that a few months back he would have said yes but now that Uber has an upfront ride cost he wouldn't make any money while were were sitting in the driver through line. I had to eat so I offered $15 on top of the fare, great results, would ride again.
edit: It occurs to me that while users are offered a static fare, drivers could still be paid based on miles and minutes. That's obviously not how the driver in my example understood his compensation but it _could_ be the case.
Basically if you want a sink replaced you can define what the sink will look like and function etc but not which tools they use to fix it. When someone is providing core business functions for a year+ receiving constant directions for short term tasks has direct customer interactions thus representing your business etc they just don't have much wiggle room.
If riders are quoted a longer than optimal route, then that appears to be deceptive to me.
If you contracted me to install cabinets in your kitchen, I couldn't defensibly take 1 year to install them, if I estimated 3 days. This doesn't make all cabinet installers employees.
Further the scoring is separately done by the customer. So the conversation is "Can you take the scenic trip? Sorry can't." Further it goes that way because Uber drivers are employed by Uber not independent contractors connected by Uber to customers.