Casdon, Oreo, Wealthy businessmen, whether corporate or self employed, do keep extemsive records and always have. Very little is thrown out. Nowadays when everything is on line even more is kept. Remember even when emails are deleted they can still be rescued from the hard disk by any competent computer buff..
When I worked on the edge of a Chairman's office, in the days before computers. his secretary told me that he kept every work diary he had going back over 20 years, so that he could, if necessary, check on who he met, where and when, right back to the start of his career. This was someone who had, as far as I know, a blameless corporate career.