Why does becoming Catholic take a year or more?

I've always said that most RCIA programs are wretched. The teachers often don't know the Faith, the sessions are more like AA meetings than instruction and it's not uncommon to never see a priest. When Rocky went through RCIA, he saw the parochial vicar once and even then, Father was just dropping by and not giving instruction. The young man who taught RCIA was actually married to an Episcopalian minister. Compare this joke process to St. Phillip and the Ethiopian.
I was reminded of how dreadful RCIA can be when I read this essay at the Eye Witness blog by a woman who was nearly driven away from the Church by her experience.