Repairs are often done, but the insulation not replaced, or just dumped in a heap as shown above.
Most dangerous is the lack of air venting around down lights. Luckily most newer houses now have LED lights that produce far less over heating issues than the halogen lights did.
The old insulation rebate scheme was the cause for a lot of the dodgy workmanship, as everyone was entering into insulation installations to earn the easy money.
So if you own a house, it will pay to have a poke around inside your ceiling yourself, if your buying a new house, spend the extra little bit and get it inspected as the insulation may just be a minor issue compared to what else may be found.