I want to be clear - the fact that I think you got lucky doesn't take away from how skilled you are or would need to be. Self-taught != poor skills, at all. And yeah, if someone really wants to do something, they should give it a shot, market forces be damned.

But at the same time, you do need to consider the pool of talent you're competing with. If you're a self-taught systems engineer, you're going to need to be really good, AND have some luck on your side during the hiring process. If you're really good and you're competing with other really good candidates who also have a formal education related to the skill-set, your chances are slim. And at the end of the day, you gotta eat. Then again, this is the perspective of a guy in a place bursting at the seams with grads with these skills (some of whom are, of course, morons, but many who aren't but are still having difficulty breaking into this kind of work).

To anyone reading this - if you want to learn these skils, don't let some jerk like me stop you, but recognize that you are at a disadvantage come hiring time. That said, a) if you get good, you can also get lucky - question becomes can you still feed yourself if you don't, and b) they can open some slightly less obvious opportunities too (SAS business development, analytics, etc.)