For some reason our customers keep asking us to launch our services in us-east-1, which I can only assume is for legacy reasons. What I don’t understand, howev

For some reason our customers keep asking us to launch our services in us-east-1, which I can only assume is for legacy reasons. What I don’t understand, however, is what’s preventing Amazon from upgrading the infrastructure in us-east-1 and making it more stable. Is it about mitigating risk of unknown side effects and/or incompatibilities?