This is an exception and a single case does not prove that all of the companies are like that. There is enough money to bribe anybody. As i said, 50K (or so) is not enough for that.
It's a well-known problem with auditor/audited relationships. What the customer wants is a clean bill of health after an easy audit. The auditor needs to be tough enough to maintain a good reputation, but beyond that they are looking to maximize volume. The Economist mentions this every year or two [1], and they're especially concerned when auditing firms do a lot of financial consulting for the audited firms. Then there's an even stronger incentive to make the audit generous.
Another good analogy is medical marijuana cards in states where marijuana is supposedly only for medical purposes. In theory, doctors are careful gatekeepers. In practice, the doctors doing those certifications have a strong financial incentive to certify as many people as quickly as possible. I've lived in San Francisco, and I've never heard of anybody getting turned down for one of those cards.
Another example from the financial crisis is the fact that many credit rating agencies gave triple-A ratings to CDOs that were later downgraded to junk status. Guess who selects and pays the credit rating agency? As it happens, the very financial firms who originated the CDOs and want them triple-A rated to sell.
