Literally just had this situation come up in a recent 1:1 with one of our junior devs.

He asked about being able to work on greenfield projects focusing on AWS technologies.

I had to go into a historical context data dump on the value of addressing technical debt (the project she is being assigned to), and how that frees us up to work on the cool and shiny projects.

I think it landed, but I could see some of the fire slightly snuffed out of him.