Technically that would mostly work but IT leaders at banks and insurance companies would rather pay high premiums to IBM then stick their neck out endorsing anything risky. Renegotiating with IBM is the safest career move at such places. Cloud is steadily edging out mainframes at banks but a lot of old guard IT leads are circling their wagons around old blue because learning how to do high resiliency on cloud is new and scary, but old blue is safe and well understood.