As the legend goes, an MVP is not even a prototype, but an ad or a landing page that describes an idea to see if people respond and/or comment on it in a usable way. The prototype form of an MVP can certainly be thrown out in favor of a new codebase, and at any rate prototypes as a generic industrial concept are routinely built by independents, contractors and small firms before the manufacturing decisions have been made, before going to a larger concern to build the product as refined from the prototype. That is, prototypes are commonly used to generate funding for the actual product. Therefore I don't think being an MVP coder who can't or won't move on to the final building stage is anything to be ashamed of, and not anything to blame like this consultant does. Not only that, but a lot of product-stage coders are terrible at greenfielding.