> The card issuer could easily institute a "no retaliation" clause in their contracts that forbids deactivating a user's account for a sustained chargeback.
On the contrary, AFAIK some banks or at least payment processors now clearly state than some "sharing economy" services cannot be subject to charge backs, or payment reversals, like if you use Paypal for a Kickstater. So it's basically the opposite of what you wish.