The twelve steps are common sense and nowhere in the Big Book does it say you must attend meetings for life, nor does it mention sponsors. In fact Awuh who is an AA historian, will know more about this than me, and I hope will enlighten you.
The end of the original BB was to spread these 'principles' to everyone, not just alcoholics, then it was edited. It's basically the tenets of Christianity, morphed with other sound spiritual principles, plus William James' spiritual experience beliefs. BillW was a very well read person.
If AA suits you, keep attending. If not, continue practicing its principles and expand into other areas in addition.