Code bases that you "work in" (maintain, etc) solve real world problems, and solving those problems should trump cleanliness every time
Codebases that are clean are typically showcase examples that sit on a shelf to be admired and appreciated.
Only if you value your time more than the users’ time and your fellow developer time. Code are run and read more than they are written. You may need to do some hacky coding, but they should be small in scope, surrounded by warning, and have a ticket filed for properly resolving the issue. Otherwise, it’s not worth it.
Sales does.
If the developers say something like "well this will take 3 weeks longer to do correctly". They'll be replaced by the code monkey that can turn a POC over to the customer in 3 days.
Reality does not live up to our dreams.
Well, I haven’t met any experienced developers that say this sentence. It’s career suicide in most cases. More often, an agreement about scope and delivery is reached and workload gets reshuffled. Customer battling with POCs to get their tasks done are soon to be ex-customers.
You gotta use the language that folks speak in order to get your point across.