Wow, sounds like maybe you HAVE been going to church with me!
Would you believe that our (former) pastor rarely even gave an opportunity for people to receive Jesus? Rarely was there an altar opportunity. I suppose he was just being "Seeker Friendly"...
You sound like you come from a different church culture than my upbringing. We were Baptised as children and we were taken to Sunday School and church services so that the beliefs of the church were instilled in our fiber. Then we studied the catechism about the doctrines of the church and were Confirmed.
We didn't have special calls to come to the altar to accept Christ as we had always had Him there in our lives and breath all along.
Yet, still God called me to Him, took my life and gave it back to me when I was eleven; and when I was much, much older He called me again to accept Christ in a new commitment.
So, I think your altar calls to accept Christ for the first time or anew are a special thing that maybe more churches should adopt.