How? I've got no way to judge the security / responsibility of any CA. The amount of money that they charge may have no relation to their behaviour. I don't think anyone has claimed that the CAs who issued wrong certs were charging less than their competitors. You can't blame the CA customers for this.
Of course, the CA would then be incentivized to publish their procedures and show how they intend to fix the breach, which shouldn't have happened in the first place, to regain customer's trust. Or go bankrupt. Let me tell you they wouldn't let their employees do mistakes.
Customers who stay, in the situation that it is discovered that Symantec issues another rogue cert, which causes Mozilla to completely revoke Symantec, can later sue Symantec for harming their business by not applying their public procedures. And here's how the economy gets rid of bad actors. The rule is much tougher for cloud machine providers (EC2 and DO): Should they lose one customers' data, everyone would leave them and go bankrupt, that's why they don't.
In parallel, losing a CA doesn't harm the customers very much, even for amazon.com. They can buy a new certificate in a matter of hours. bzbarsky even says it's commonplace to have the certificates signed by 2 CAs.
There would be a slew of reviews of CAs, judging their perceived odds of vanishing in a puff of paperwork, if there was an interest in issuer stability. CAs themselves could probably offer value-added features like guarantees backed by outside parties (i.e. an insurance product) that would pay costs associated with certificate reissuance in the event of malfeasance or incompetence on the part of the CA.
The market would provide, but there has to be demand. Right now there's no demand, because the consequences of getting a cert from a crap issuer has, historically, been approximately zero.
How CAs respond to issues on these mailing lists and in bugzilla is also pretty telling.
In this particular case, there's been concerns raised for several days. An extra vigilant web site operator who sees these discussions might perhaps come to the conclusion that it would be wise to evaluate switching CAs today, perhaps.
We're all doomed then! Asides from LetsEncrypt, most CA web pages are full of marketing fluff :)
I've just been reading through the mailing list discussion, and from that I agree with you completely, WoSign looks pretty incompetent in their responses. If I had a WoSign certificate, I'd definitely be looking around to get an alternative now. However, that's a bit late for 'people power' to force CAs to act better.