When it was first introduced, the vast majority of people had a strong work ethic and people who didn't contribute, tried to scrounge or didn't provide for their family were looked down on by their neighbours. This attitude has largely disappeared and now living on benefits has become acceptable and some even brag about it, ie there is no shame anymore. Add this to the fact that any family who has never worked, with children is entitled to the same benefits as those who have paid taxes all their lives, this is mainly due to the policy of trying to lift all children out of poverty which gives the feckless a licence to print money by having more and more children, knowing that as far as the authorities are concerned, the children must be cared for even if that means throwing money at the parents.
We need to get back to the initial concept, ie a safety net for those who fall on hard times and the more you have paid in, the more you can get back if you ever need it.
The system as it is is unfair to those who have paid in all their lives compared to those who pay nothing.
The problem is that in part the welfare state has changed to reflect the fact that life is just more complicated now than it was when Beveridge wrote his report. While there are certainly reforms that can and should be made, we can't return to the initial concept completely because that world no longer exists.