Not all magazines are published every month. Some are bi-monthly, some are quarterly, some only come out once or twice a year.
TBH, if I looked through a magazine and found it to be worthy of $6.99 at the time of purchase, I wouldn't feel a bit cheated if I realized it was a year old. The information in it is still just as valuable, is it not? Besides, sometimes the older magazines are harder to find!