> They must have got some things very right in the original architecture to be able to do that. I'd argue they (and many larger, older, established etc systems

> They must have got some things very right in the original architecture to be able to do that. I'd argue they (and many larger, older, established etc systems) may not have, but it's part of how it works so while it may not be the best it's the one that is working right now and earning them money - working (and earning) software always trumps correctness etc, in practice.