The Larger Corporations can lower cost and be compliant because they pass the cost of Compliance on to the suppliers not the consumers. All of the Big Box Stores practice this.
The smaller companies that are currently sourcing product overseas, will tend to go with a trading company. When they make the annual trip to "Inspect the factories" the trading company will take them to the "Model" factory.
While there, the Importer of Record will see how wonderful the way of life is for the factory worker. And how the factory is compliant in every way.
Unless you actually hire somebody in that country as a full time employee (and even then you can not trust them) a company may never get a full picture of where the goods come from.
And you are totally right. Compliance is a farce. China is still not allowing third party security inspections and validations for U.S. Customs purposes. Even with the possibility of losing money and orders from prospective new partners, China will never fully comply with any worldwide Labor criteria.
A good customer of mine once told me "If a Chinese Executive tells you 'Do not worry, I have taken care of it!' check for your wallet. You just had your pocket picked."