> As this article pointed out, there's a vast asymmetry of information, which prevents an efficient market, even in theory.
What kind of theory are you using here?
There might be some theoretical reasons to expect that symmetric information (and a few other conditions) will lead to an efficient market.
But that doesn't mean that a pre-existing information symmetry is necessary for an efficient market.
The classic example is the 'market for lemons', a paper about the information asymmetry in the market for used cars: layman buyers typically can't judge a used car well via a short inspection.
That was supposed to prevent an efficient market where you can buy quality goods.
Of course, the business solution to this problem is fairly straightforward and profitable: reputation.
You run your company with strict standards, so over time you build up a reputation and charge a premium for that. In addition you can sell warranties, too.
A really simple example is white goods: it's really hard to judge a dishwasher when you just see them in the store. There's reviews I can look at, but I can also just go and buy a Miele dishwasher. They are pricey, but I also know that they are extremely high quality and will last.
For a while, Miele could ride that reputation and sell shoddy products until the market catches up. But it's more profitable for them in the long run to defend their reputation. (Also employees would probably rebel against a change in policy. Many people like to take pride in their work.)
This is all without regulation having a binding impact: shoddy dishwashers are just as legal as premium dishwashers.