Chargebacks are only as aggressive as the bank's customers are willing to enforce by leaving / suing against the vendor's level of customer expectation of service. Outside of a vocal minority, no one is going to want a card that doesn't work on amazon.
The playing field has been rapidly shrinking, and the customer base is much more stressed and unwilling to fight.
Not to mention that's also roughly around the timeframe that binding arbitration really got pervasive.
