||a proto, as opposed to a concept. Conceptual rederings/builds are always a far cry from the production build, but by definition, the prototype SHOULD be a pretty close representation of what will hit showroom floors.
Based on how my company runs projects, once the prototype is built, most changes that follow are a result of testing and final compliance reviews. Granted, I'm inthe crane industry, but the product development process is typically pretty similar - especially for things like this that are failr complex.
I think 2022 is fair, later than that, something went wrong. Of course, late and great is better than on time/early and plagued with problems.