If the cases are more frequent I would think its more complicated than people simply not doing their jobs properly.
Firstly multiple services and agencies (surestart, health visitors, CAHMs, adult MH, social services , police etc) have been underfunded and cut to the bone so they are spread too thin, or harder to access as well as people potentially living more isolated/insular lives that they don't necessarily have a support network from friends/neighbours/family , before you get to social service intervention.
In this instance it seems the SW was the only person concerned enough to raise an alarm after not seeing, hearing or speaking to the family for a week.