If I have learned anything in this life it is this; there is a vast difference between a "business" and a "hobby" and a "hobby business". I've seen many a good man or woman start something because they were passionate about the product/service. After a short period of time, it became apparent they were more into a hobby rather than a business.

Nothing wrong with a hobby just as long as you realize you likely won't make the serious $$$$ you thought you would make.

The big time Mercedes Sprinter RV people have invested thousands and thousands of dollars into tooling plus training for their workers. It isn't impossible to succeed but let's just say it might be difficult acquiring the necessary resources, i.e. money, tooling, trained workers, factory, etc. to compete with those guys.