The biggest reason is a lack of time--from my kids' school and extra-curricular activities, work responsibilities, and projects around the house--I could not squeeze an extra minute to open and look through a pack.
However, the urge to get back into the "card game" came back, but not how I would have thought.
A regular at my LCS who was a trading partner at first and later a close friend passed away from cancer a couple of weeks ago. He had been battling the disease off and on since being diagnosed 17 years ago, and when the cancer would go into remission, it'd come back as if it never left.
One of the crown jewels in his collection and perhaps his proudest accomplishment was his run of complete Topps baseball sets, starting with the 1962 edition. When I first ran into him, I was beginning my 1963 set, and he helped me out with a bunch of commons for almost next to nothing.
He was always encouraging me to be on the lookout for deals on common lots and occasionally take the plunge and spring for a minor star or star to keep the chase interesting.
About February or March, he found out the cancer was back again, but with a vengeance, and he would be lucky to have six months to live.
He tried to make a few visits to the shop, but by May, he was pretty much confined to his home and under hospice care.
His passing has made me reflect on what a great hobby collecting is, and the friendships and relationships with other collectors are not to be taken for granted.
I'm going to get that '63 set finished, hopefully sooner than later, and know that he'll feel just as much pride and accomplishment as I will when I cross the last number off my want list.