There is a pattern in software engineering of:

* Project exists

* New employees come up with idea for efficiency improvement

* Months spent implementing. Old codepath becomes legacy.

* New thing now has extra features bolted on during build.

* Efficiency of new thing turns out worse than original, but now the new features and 'less technical debt' are the drivers.

* New thing launches, old thing deprecated, but there is little real benefit to all those months of work.