Yes. And they have much better mechanisms than DKIM available which they should use instead. In fact, with reliance on DKIM you create the distorted incentive

Yes. And they have much better mechanisms than DKIM available which they should use instead. In fact, with reliance on DKIM you create the distorted incentive that one company might want to fake getting hacked to claim an email they sent is not authentic. As a matter of fact, they might even be so sneaky as to send individual emails without DKIM signatures, with a policy set for the recipients to not reject those emails. Since most email clients do not display this discrepancy in a lack of a DKIM signature, the recipient might not notice and then the sender can later claim forgery. So then let's not rely on something so unreliable if you need reliable authentication.