Perfect is the enemy of good. What you're describing happens just as frequently in regulated markets (the police works fine for a certain sector of this country and not so great for another...), its just that regulated markets offer the false promise of perfection. At the end of the day there's no magic, its people at the end of all these services. So what's important, as Milton Friedman used to like to say, is not finding the right people, but getting the wrong people to do the right things.
The people that visit Las Vegas don't vote in Las Vegas, so what incentive is there AT ALL for the government to protect the customer? This is basically the worst edge case for a regulation: the regulators only receive votes from one side of the arrangement, so who do you think they'll bias? Unless taxi abuse got so bad that it actually affected tourism, then I assure you it will always slip between the cracks. On the other hand, a business that cares about solely this problem will actually figure out a way to solve it.
As a customer, I want an easy button to affect my contractors' businesses based on their performance. But when I am on the receiving end, I want to know that the negative reviews are legitimate (not subject to discrimination or gaming) and that the punishment is proportional to the crime. These goals are at odds, and I hope the latter is not sacrificed in the app economy.
You're right that the tourism industry is probably the worst case for democracy to ensure accountability of regulators to the people. But at least all punishments imposed by the government are subject to the court system; the government does not take away your license to make an income without evidence that you actually violated a law. Furthermore, government is subject to other mechanisms to be accountable to the people e.g. FOIA requests (vs Uber, who keeps their data exclusively for themselves). I worry that industries will be controlled by companies that care only about the aggregate revenues and are not accountable to the people,
"without evidence that you actually violated a law" - oh, you mean the laws/regulations written by politicians who do so at the behest of entrenched, crony corps to control markets, suppress innovation, and defend their stagnant products/services?
"But at least all punishments imposed by the government are subject to the court system" - Guess what? There's this nifty thing called civil court, and if we just made filing legitimate small claims easier, faster, and more effective, people could use this outlet to organically push back on bad behavior without the need for centralized regulation.
"its just that regulated markets offer the false promise of perfection"
No: it is just that regulated (I prefer the name public but anyway) markets offer the possibility of legal defense by definition. Thus, the customer is not left defenseless.
However, this applies possibly much more to Roman-law derivative States than to the US.
Who cares what you have by definition? What matters is whether you're on average better off in practice.
It's cold comfort to have legal recourse technically available, if it's never worth the time and money to pursue it. If you have to seek recourse at all you've already "lost" --- the recourse never really makes you whole, given your broken expectations, time to pursue, etc.
Consumers have a defense with private markets -- use the competition. The problem with regulated public markets, such as taxis in NYC, is that a consumer has little choice, thus, unless they want to spend hours of their time dealing with an inherited embedded and political bureaucracy, there's little alternative. It's like restaurants, the bad ones tend to go out of business eventually. But imagine if restaurants all sucked and they were enabled in their suck by a government imposed "medallion" system and a supply of those medallions not controlled by market demand but by the restaurant mafia themselves, then there isn't any alternative, so your stuck with inferior quality and impossible barriers to entry controlled by your competition. Removing barriers to competition is the absolute best way to improve a market. Prices drop, service has to also improve. Those that perform a bad service at a high price quickly die because, if I don't like it, I can easily choose a substitute. Restaurants are a great example. You certainly want some level of regulation, but only the minimum amount to protect the health of the public. So in the public transport area, background checks should be required, insurance should be required, safety inspections should be required, but silliness like taxi medallions ought to be eliminated. To be clear, I am not against regulations, but I am against market regulation. There is a subtle but important difference.
"It is just that regulated (I prefer the name public but anyway) markets offer the possibility of legal defense by definition." - I think you may be forgetting an entire area of the judicial branch: Civil Court. You can, in fact, sue a business for: representing their product incorrectly, providing service other than described, not sticking to the contract you signed, etc, etc.
We could just as easily simplify, streamline, and reform the civil tort system to allow people to file and address legitimate issues quickly through organic, judicial means. But instead, people, for god knows why, believe it is easier and more effective to have politicians appoint a bunch of crony farts to pass hundreds of thousands of pages of regulation that make the 95% case of good business operation harder, while most often failing to catch/fix the 5% of time things go wrong.
Civil court is a venue in which action based on existing laws and regulations are pursued. It does not substitute for actually having the laws and regulations which provide the bases for actions.
"[...]regulated [...] markets offer the possibility of legal defense by definition. Thus, the customer is not left defenseless."
I don't know about the US but in Germany and Austria this could not be more wrong. Your ability to object through legal procedures is highly dependent on the regulatory field you are working in.
Is is most awful in fields with state monopolies like work permits or licensing.
The people that visit Las Vegas don't vote in Las Vegas, so what incentive is there AT ALL for the government to protect the customer? This is basically the worst edge case for a regulation: the regulators only receive votes from one side of the arrangement, so who do you think they'll bias? Unless taxi abuse got so bad that it actually affected tourism, then I assure you it will always slip between the cracks. On the other hand, a business that cares about solely this problem will actually figure out a way to solve it.