I don't think relaxing vehicle standards or driver background checks is good for anyone - and requiring your contractors to have certain equipment sounds perfectly reasonable to me.
That doesn't really matter. Nor is it really true, since you inevitably interact with the driver. And it's understood that drivers are humans, and they are different.
McDonalds operates a franchise, you got the same thing, but still, different companies.
Yes, Uber had not structured itself as a franchise, but the use of [sub]contractors to provide a service with a controlled and sort of guaranteed (and well marketed and branded) quality - in itself - doesn't make the drivers employees.
I think the line between contracting and employment is up to the host society to draw.
Usually tax authorities have a few simple rules and if you are in compliance of at least half of them (or if you break at least X of them), then you are a contractor (or disguised employee). For example exclusivity is important here, the rule states that if a contractor gets more than 50% of its income from one entity, then that's one strike (and there are 5 other rules).
Of course it seems in UK law the drivers have standing, so it means there must be some statute about when a contractor is to be treated like employees. (For example, let's say you can't use temp workers, contractors like regular full time employees and not give them free cafeteria, if your regular employees have that perk.)
But of course this is meaningless in case of a 2 party problem, because it doesn't help determining "employmentship" vs "contractorship".
So what'd be a clear and fair way to test for the quality of work relationship?
https://www.forbes.com/sites/robertwood/2013/09/06/32m-domin...
Uber's business needs are somewhat at odds with its legal case here. From a branding standpoint, Uber wants you to think of yourself as interfacing with Uber, not individual drivers. They want you to believe that if you call an Uber, you're going to get a certain level and quality of service.
Contrast something like HomeAdvisor, which is undoubtedly an aggregator for contractors. Home Advisor doesn't tell its contractors what kind of equipment to use, it doesn't kick off contractors who don't achieve a 4-star rating, etc. It's explicitly marketed as a service for finding contractors, not a company that performs the service directly.