I want to be an instructor some day with my own club. This is why I peruse rank. Nobody wants to train with a Sankyu instructor.
To some extent this is true, as most people tend to attach a great deal of importance to rank, both within martial arts organizations and in our society in general. Certainly, the clueless masses will always gravitate towards rank over skill; this is why, at an aikido camp I attended a few years ago, Moriteru Ueshiba's classes were far more popular than those of Nobuyoshi Tamura. Ueshiba has the rank, and that's what most people want, even though it is obvious that his skill level is nowhere near that of Tamura.
However, the discerning student can tell the difference between rank and skill and will seek out those with skill, regardless of rank. Without rank, you will have less students, but they will be of higher quality. I myself claim no rank in any of the arts that I teach yet I have students who hold dan-level rankings and are instructors themselves in other arts. As far as I know, guys like Akuzawa and Dan Harden also claim no rank, yet they are still quite publicly attracting students, also in many cases ones that are advanced practitioners or instructors in other arts. In fact there are entire arts (taijiquan is one example) where there is no ranking system yet they don't seem to have any problem finding students, even if they don't have quite as many.
There is no question that rank is very effective marketing tool, and if you want to build a large dojo or organization then rank will be useful in helping you do that. But is not necessary in order to teach or attract students, and in my experience (in several arts and organizations) the kind of students who are primarily interested in rank and organizations that award rank is much different than the kind who train just for the sake of practicing the art without needing to ascend some formal hierarchy in the process.
Of course, I'm referring mainly to non-competitive arts here where rank is awarded primarily on political rather than technical grounds. It's a little different in arts like BJJ and kendo where rank has a more direct correlation to something technically meaningful (and as an aside, one thing I respect about kendo is that they not only test for rank all the way up 8-dan, but the ZNKR 8-dan exam is one of the hardest exams to pass in the world in terms of failure rate; compare that to the typical aikido organization that only tests up to 3- or 4-dan and where almost everyone passes these 'tests').