Very Large Enterprise is very hard to change, or rewrite, especially old systems. Our company mostly sells contracts to large corporations / government institutions (1500+ employees), with an insane amount of transactions, functionality, etc. Even with the latest models you cannot automate everything, the world is far too complex, and there is quite a bit of pushback when anything changes.

In order to keep some of these extremely large contracts (using Samsung as an example here) for example, we had to revert certain changes that were global but now we have a "Samsung version" because we want to maintain a large presence in Asia and Samsung leaving would be a huge blow.

At this scale, code isn't even the bottleneck, it's customer wants, politics, etc.