There are several factors that determine the number of attendees to educational seminars.
The first factor that determines the number of attendees to educational seminars is how well the educational seminars are publicized. The better the publicity-building work, the higher the number of attendees who end up showing up.
The second factor that determines the number of attendees to educational seminars is the caliber of speakers and other facilitators in the said seminars. Seminars facilitated by respected ‘authorities’ in the various fields often end up being very well attended.
The third factor that determines the number of attendees to educational seminars is the cost of attendance. Educational seminars that are perceived as being to expensive are typically poorly attended. That is especially the case in situations where the targeted attendees are students. You have, after all, to remember that most of these students are typically folks who entirely have to rely on the funds they get from the government in the form of federal student loans, or the so-called My ed account direct loans. And if the loan figures given at sites like fafsa.gov are anything to go by, it becomes clear that such students can’t really afford to attend educational seminars that are perceived as expensive, however much they may desire to.