> even when there are better things that already exist

That's a "big if".

Lots of times what's there is a nightmarish tangle of technical debt left by previous greenfield devs. The dev who gets to maintain and evolve this dreck is the sucker, scapegoated for ever slower development.

Canonical example: on-call AWS engineers working hellish overtime to close tickets on one of AWS's many terribad fragile codebases.