One thing to mention is that many of these designs were submitted as part of an industrial design process and not necessarily the result of a full-on engineering process. Some of this stuff is still in wood mock-up stage. There may have been some computer modelling done on it but in many cases not much more. I would consider it to be more of "functional art" than a consumer-ready engineered product. This doesn't mean that the concepts won't work but they will likely need many refinements before they're ready even ready for a testpilot to take it out into a real environment.