it depends. I think it's fair to say that each case (possibly not every one, but lots of them) presents its own challenges, and mostly the systems set up to deal with them succeed in doing so, but occasionally they don't.
To know just how badly things are going we'd need to know more than just the few headline cases you've mentioned (and they are fairly few) and how many times social services intervention has made a difference. In other words, the non-news that doesn't make the paper (and is immeasurable anyway because how can you count catastrophes that didn't happen?)
So it's quite quite possible that lessons are learnt, and that subsequent similar events are dealt with more successfully.
Just to add that the big problem in this case seems to have been that the mother moved around a lot, and services maintained by individual councils aren't necessarily set up to monitor such cross-border movements. Should they be? Can they be? Is it economically possible at a time when councils are under financial pressure? These will be lessons that have to be studied this time round.