RE: The fall into Homelessness.
Not everyone is a kind hearted person. The agencies; enabled by the personal choices of their employees are vile, and there is plenty of evidence to support the fact. You could start with looking into Former Senator Nancy Schaefer's work if you truly want to comprehend what is happening on a large scale all over the world right now with these agencies. I've seen it myself, so I know. Brick by brick they are isolating families in a methodical manner so that the masses won't put two and two together in time to help eachother. There's a lot of documentary work on the horrors being perpetrated by these agencies. If you really believe what you have said above, I would implore you to look a little deeper into the issue. I'm not trying to offend anyone (unless you steal babies for pedo's for a living) with this comment, but we've been lied to people. It's about control, domination, and is part of that big picture everyone is trying to suss out. The dots are all there to be connected.
I wouldn't be surprised if that's a case in some countries, with commercial entities running big orphanages and bribing officials. In other countries and time periods, maybe the CPS is abused for political control, i.e. targeting parents by their political views. I wouldn't be surprised if "someone told us the parents are socialists" would be sufficient reason for the US CPA to react under the McCarthy age. But if you're implying that all the CPSes around the world has some kind of shared agenda ... then I must say, that do sound like one of the more crazy conspiracy theories to me.
Parkinson's law may be relevant though, any bureaucratic organization do have some internal growth pressure.
Such a system can only be based either on personal opinions from their employees or on stupid rules (like "you must be registered on a permanent address of living"), both things may be equally bad - yet, what are the alternatives? While for some the obvious answer would be "kill the whole agency", I do believe it's important with such an agency; children do have rights, and they are not able to look after their rights all by themselves.