Some people (such as myself) have a hard time landing interviews for some reason[1]. During my final year in college, I sent out no fewer than three dozen resumes to potential employers (all of whom were hiring); only four of those companies asked me to come in for an interview.
[1] Note that that "reason" was no doubt due to my inexperience and not knowing how to properly market myself at the time.
Not getting contacted back can many times also be a fault of the company hiring. Sometimes it takes weeks to hear back, sometimes they want you to stop by tomorrow while you clearly wrote you're on the other side of the country.
Just another indicator not to take job hunt too personal and making sure to look into every opportunity available.
[1] Note that that "reason" was no doubt due to my inexperience and not knowing how to properly market myself at the time.