Peer-to-peer markets used to be simple: there was eBay. If you had a broken laser pointer you wanted to sell, eBay was the place to find a buyer. Then came the local marketplace Craigslist and, before long, peer-to-peer markets were linking buyers and sellers in every market imaginable: crafts (Etsy); chores (TaskRabbit); transport (Uber); accommodation (Airbnb); consumer loans (Zopa); and even booze (Drizly).

It was exciting, for a while, to realise that you could actually get a car home on a Saturday night in San Francisco, or make money renting out your attic, but the backlash has been simmering for some time. That backlash mixes two complaints, elegantly exemplified when a group of taxicab owners and drivers sued Uber in Atlanta a year ago.

“Uber has been operating in Atlanta with little concern about the safety of their passengers and zero concern for the laws that protect them,” said one of the plaintiffs in a statement to The Atlanta Journal-Constitution. “Our incomes have steadily dropped since Uber started and legally licensed drivers are leaving the business.”

In other words, peer-to-peer services such as Uber are said to be hazardous, and they are also unwelcome competition for incumbents. (Several studies have supported the common-sense conclusion that these new competitors threaten the revenue of existing players.)

These might seem very different issues. It’s one thing to worry about signposting fire exits when you let out a spare room on Airbnb. Protecting the profit margins of fine upstanding local hoteliers is another matter.

Yet the two questions are inevitably tangled up, because both touch on the way incumbents are regulated. One would hope that regulators protect consumers, employees and the public by making it more difficult for drunks and sexual predators to drive cars, for firetraps to host unsuspecting tourists, and for employers to exploit workers. But some regulations seem designed more to protect insiders than to protect consumers.

Consider the New York taxi medallion system: you can’t drive a taxicab without one, and they’ve been million-dollar assets at times, often owned by investors and leased to drivers at a rate of $100 or more a day. New kids Uber and Lyft not only compete for passengers, they compete for drivers too, who may prefer to pay commission to these new players than the flat fee to the medallion owner.

Taxi medallions are a scarce asset created purely by a stroke of the regulator’s pen, and you don’t need to be a hardcore libertarian to conclude that, in this case, the regulator is motivated by protecting the value of this asset. Nor does it take a free-market fundamentalist to believe that if consumers think that taxicabs provide a safer service, they will pay for that safer service.

It may help to approach the debate from a different direction. Are these new players providing a valuable new service or are they merely an arbitrage play, using technology to sidestep taxes that others must pay, and to limbo-dance under regulatory hurdles that rivals must jump?

If the economic value is real, then it is up to the regulators to figure out how to unleash that value rather than trying to legislate it out of existence.

A new study of peer-to-peer markets by economists Liran Einav, Chiara Farronato and Jonathan Levin argues that the economic value is there all right. Peer-to-peer markets make two things possible that were previously hard to imagine.

The first is to make arid markets lush and fertile. The quintessential example is eBay, enabling buyers and sellers of the quirkiest products to find each other and gain by trading. Etsy fits the eBay mould, with sellers who will knit you a cuddly toy designed to resemble a dissected frog, a product that seems unlikely to find a niche on the high street.

The second peer-to-peer trick is to introduce part-timers into the market to meet surges in demand. It’s inefficient to build hotels just to cope with the summer rush, or taxis to cope with New Year’s Eve but, if the demand is there, peer-to-peer markets can pull in a bit of extra supply. As a result, it should be easier to get a cab at 11pm on a Friday, and prices for hotel rooms should be more reasonable during school holidays.

Peer-to-peer markets are well worth havin. The challenge for regulators, then, is to catch up. How should Airbnb landlords who let a room for 10 nights a year be placed on a level playing field with regular bed-and-breakfast landlords? Are Uber drivers employees (as a California labour commissioner recently ruled)? Or freelancers using Uber’s software to help them do their jobs (as Uber insists)? Or something else?

James Surowiecki, writing in The New Yorker, recently argued for “something else”, and called for a regulatory overhaul to give “gig-economy workers a better balance of flexibility and security”. That sounds like an admirable aim, although achieving it isn’t straightforward. Giving pensions, vacation rights or unemployment insurance to Uber drivers or TaskRabbit “taskers” would require both clever rules and clever admin systems.

Peer-to-peer markets may once have been simple; now there is more at stake than the occasional broken laser pointer.