Growing up, there was practically no system at all for helping people like us. I can recall about 2 or 3 times during my school years, that sby (teacher) suggested I "talk to someone". But due to having by then (~8-9 yrs old), developed extreme pessimism/hopelesness, I didn't bother. And I did actually talk to a school councellor one time, later on (due to a teacher referring me), but I was & felt way "too far gone" by then for it to help at all (I needed "professional" help, not just a school councellor). But almost all people (teachers, pupils, family, relatives) just passed it off as 'oh, he's just a shy kid', and left it at that.
So yes, I did "slip through" the system (or lack of one), well-and-truly 100%. And for a time (esp when "s**t-hit-fan" starting in my early 20s) I was very very bitter about it.
It was only when I started getting heavily into self-help books/stuff, and began making some very minor improvements, that I also began to take responsibility for my life & my problems, for the first time in my life (before then I had blamed life, others, been bitter, angry, etc)
And it doesn't seem things have gotten much better in the last 20 or 30 years. So then, as per usual, the only people who can help the SA child, is themselves. But the problem as I found, is that at that age they haven't really got the "tools" to do so. And so they end up suffering in silence, for years and years and years.
But who knows, maybe some day the "system" will improve??