I know people that are still in it a year later and also people that have failed out on the first quota.

It is possible. It is NOT EASY. Work your ass off everyday. 

In the interest of full disclosure, my friend that is still in landed a few large accounts (2 of about $3 mil) that have carried him over several hurdles. He has not stopped working and continues to push very hard. Those numbers are no joke. Im not sure what the normal quota is but he has to get 12 mil under management in 2 years. He was given 3 months to get settled, meaning his first hurdle was 6 mo from his hire date. He started working the first day in the office and was networking (not soliciting) before he started.