Additionally on A: the people who will be stuck maintaining this contribution for years and years have a different view of the pain.
Pushing a 90% solution through is a ‘win’ for the coder who is leaving, and hurts everyone on a continuing basis. It’s bad accounting, and lets the consultant look good for making the team perform worse (and look bad later).
And, IME, if that 90% solution needs a 100% rewrite after 40-80% burn in bugs and error chasing? What once was a bit behind is now way behind with staffing issues. Sunk costs don’t create extra budget.
Do It Right The First Time doesn’t always apply, only mostly always. Some people are insecure and territorial, yeah, but some know what their job is.
No matter what you do, entrenched engineers will make SURE they will be the only ones maintaining everything until their retirement, because they will make life impossible for everybody else until they leave.
Entrenched engineers don’t want to you to alleviate or god forbid share the pain. Pain is good for employment security. And if the ship goes down, they’ll make sure they’re the last one to get fired, because there’s nothing the entrenched engineer fears more than having to job hunt.