So only games that are made from scratch can charge full price? What about reusing code? Engine? Animations? Textures? Lighting system? Rendering backend?.. Games are made of everything that came before, being angry about a game using assets that were originally developed for an older game is like being angry about a movie reusing props made for an older movie, should they burn all of the Christmas decorations between one movie and the next? Or can the studio hang the same glass ball on two different movies? Does that detract from the movie? Will you really only consider it’s worth the full price if all props were made exclusively for that movie?..

I made a tool that migrates from one DB format to another. Then another format was introduced. Of course I reused the assets from the tool to expand the tool to migrate to the new DB format. But then I know more of what can go wrong with the tool, so even then testing took longer, but the tool ran cleaner.

Every game reuses assets. Some are just more clever about it than others.