I borrowed this snippet of a photo from a site that represent an example of what looks to be a small but capable and apparently growing small business centered around heavy trucks, trailers and equipment. See http://www.earthtoearthllc.com/ .
If this heavy truck related business is typical of what I have seen, it was started by individual who had at least some related experience, was personable or competent enough to get some early business, a dream of independence and had a bit of cash and or credit to buy or rent the proper tool and put it to work.