The "solution" is simple.
Fine the carriers, HEAVILY, for allowing known vulnerabilities to continue. Businesses operate on a cost-benefit ration. If mitigation is too costly, they will not see to it, instead accepting fines and lost business as a minor "cost".
Make the fines so astronomical as to be a true incentive to mitigate the vulnerabilities and protect their customers.
Nothing else will work.
Biting the hand that feeds IT
