I gave the certification rules because this applies once a union is certified. The big question is whether Uber drivers are employees and eligible to form a bargaining unit.
I don't the answer to that.
Let me try again, from my own experience in the first years of two nascent unions of freelance, independent contractors establishing themselves in the film and TV production biz.
The labour laws that define unions were written for permanently-established employers who hire workers for indefinite periods. Not only were we engaged short-term, the producers who engaged us were invariably incorporated only for the expected term of the production. When it produced the reels of film/tape/hard-drives it sold them, paid off its shareholders, liquidated any assets it couldn't avoid acquiring, paid its last taxes, and was 'wound-up' and disappeared.
Down to the lowest labourer, everyone who didn't have a piece of the property was on a week's notice at best. Most of the better-paid folks — from producers through any of the skilled trades and crafts — billed their expertise and labours through personal corporations, often also supplying seriously expensive and essential production equipment on rental as a sideline. But many preferred the straightforwardness of employer-employee, and production companies had no real difficulty maintaining both payment schemes.
Nothing prohibits any group of people from forming an association, and establishing it as a legal entity with officers and by-laws, registering it, or even incorporating it, so it can do business, hold money and do banking, and enter into binding contracts. They can set up insurance plans and benefit schemes and training programs and certification schemes.
And if most of the folks working 'there' (however that is defined) all belong and say they want the same thing, the the folks who want the work will have to figure out if they can more easily afford that, or the disruption of finding new workers. That's elementary capitalism
That's what we did. Over time. And it worked for both the technician's association I first was part of, and for the director's guild I later joined. Both had lots of internal argy-bargy about whether they were or weren't a union, particularly the directors who most definitely could and did fire and hire people. But in the freelance world, just about anybody can wind up doing that. And the people we worked for wanted it that way; it let them focus on the money. So for both sides that stuff was irrelevant semantics. The bottom line was getting to handshake time most efficiently. A couple of folks across a table did better for both sides than the anarchy of hundreds of individual deals.
It all might have been a bit easier if we fitted the labour law's notion of unions, but it almost never made a practical difference on the job, negotiating contracts or settling disputes. I do remember being a witness at the OLRB in the early days, in a dispute with a producer over some incident I can't now recall. There was some argument whether our association was a union and should be there at all. My recollection was the Chair pointed out that if we were not, the case would be thrown out with the issue unresolved, so the parties agreed to proceed. Without deciding the 'union' matter.
By now both 'union's have had decades of successful existence and experience signing both individual and industry-wide contracts and both have survived many further challenges to their status.
What it all boils down to is: Union, shmunion. If you want one you can have one. Whatever the particular word you can, or cannot, call it.
Gravity may always win, but that just makes Solidarity Forever.