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.