There is some brief lip-service paid to using the same language on the front-end and the back-end, but mostly you're right - they fixed processes, not technologies.
Mind you that what you see on the PayPal sites is not all updated. This is a testament to just how deep the technical stack has been.
Other colleagues have been attacking the services layer and they are doing just as much change in that layer as my team has done on the app/frontend layer.