Yes, the unmarried DO fall through the cracks.  You are looking only at the fact that:
1) the unmarried are not excluded from holding lay ministries
2) they can receive sacraments

And according to you, that's all being a parishioner is all about.  Sorry, there's more to being a Catholic than one's "functionalism".  Are there any programs that are JUST for the single?  Discussion groups?  Retreat opportunities?  


Secondly, "irregular situations" today ARE more of the norm, than the norm.  Why is it that the very people that Jesus held up as heroes/heroines both in his parable or whom he met in actual life---were those who were seen as "irregular" or in "irregular situations"?