SpEd: A Prerequesit?

Perhaps this is a good discussion point at which to ask a couple of nagging questions. I have been perplexed and even bewildered for quite some time. It may even tip the balance for me to enter into the teaching profession, at least in the public school system.
My question stems from my own experience. I have been a substitute teacher, an education technician for Special Ed., and an all round “gopher” for our local public school district for the past 7 years. I have my BA degree in education and human behavior, and am currently grinding through the teacher certification process (yes, those blasted Praxis series teacher qualifying tests). A year ago I completed my teacher internship, and now look forward to a final career as a teacher. See my bio in the course Roster for my brief story.
It seems that while looking through my own chartreuse-colored lens I have come to an unwritten understanding that Special Ed has become the “sacred cow” or “darling” of most public school systems. I’m not in criticism of the necessity of it, since it is a federal mandate of all public schools. And, I’ve understood the need for it with students who have physical and mental disabilities. What I have observed is that it has become a “dumping ground” for many “at risk” students. Students that I would say were lazy, smart-mouthed and a general nuisance in the class. I could give a dissertation of why, in my opinion, this is done, but it would take up too much space on the discussion board, and many of my classmates would rather not read the ramblings of a novice teacher.
As I have related, I’ve been a substitute teacher for quite some time. It seemed as though 90% of the teachers, I was called in for, were SpEd techs (teacher’s aids). I had a few bad experiences, and was getting burned-out from the SpEd routine. Plus, I yearned to sub for regular teachers (no offence to SpEd teachers). I made this known to the assistant principal who normally calls me in. It has been 4 months since I’ve received a call. I’ll leave the reasons why up to the rest of the class. Feel free to comment.
My question(s) stem from observations made within 2 high schools, where I have observed SpEd technicians hired as full-time teachers. My question(s): Why does it seem that a SpEd position almost guarantees a future full-time teaching position? Why does it seem to be that a SpEd position is an unwritten requirement for a full-time teaching position? A more exact question may be: Why does it seem that teaching as an education technician in SpEd has become the litmus test for candidate teachers? Is this a proving ground like, “If you can teach here, you can teach anywhere,” as Frank McCourt (Teacher Man) related to when he started teaching in a vocational school?I’d like some feed-back on this. Help me see the light, here. Please be honest with me. I will respond.