In a market where consumers have cognitive limitations (for example, where they forget bad experiences, or frequently resort to cognitively cheap heuristics) - and where quality is costly - firms that cheat on price signals will win out.
Even if the firms are just retailers, instead of manufacturers.
Who polices the quality controllers, in a market where customers are forgetful, and not very clever?
An even bigger role for the incentive to 'be good' and not to 'reward bad behaviour'. What makes people 'good'?