I'd say you should be able to quantify it. "a ___domain model tightly coupled to CRUD primitives" is not an intrinsic evil. If you were to genuinely save money or reduce risk by, say, moving off a relational database you would just need to pick that point and motivate for a rewrite.

The much higher risk IMO is building a hyper-flexible application from the start knowing what you need today is a CRUD app, just in case in future you need something else. That's how you get shelfware and awkward conversations.