For the "serial entrepreneurs" this is an easy way to stay employed (it can be surprisingly hard to get a job at BigCorp with CEO on your resume). These folks might just start a new company, raise some money, and voila they are once again on an "incredible journey."
In my experience for each "successful" exit (where the investors made some money) you get a ticket for one free "future" company from those investors. Once you don't have enough tickets to get another company funded you either have to change venues (new people, less history), or change markets (also new people but can be in the same locale).