With that sort of thing, I tend to make certain default assumptions.
My general view for starters, then my deductions, and application to this.
When people at the top want to make or save money, it filters down the system, but by the time it gets to the bottom it's distorted. This has happened throughout history.
So in relation to benefits, here's how I see it. I'm talking about recent Tory and Coalition governments of the UK, but I don't see New Labour as awfully different on it.
Politicians want to save money. Politicians in the same party and the same government may have different motivations and understandings, but agreements on how to go about things.
So some politicians believe the rubbish that means there couldn't possibly be so many disabled people and aren't interested in having it explained to them about things like advances in modern medicine over recent generations meaning higher survival rates with disability, whether that's at birth or later in life.
Others know there are lots of disabled people but just like to pretend otherwise in furtherance of their small state beliefs or, as I see it, 'gimme the money, let them starve and blame them' beliefs. (Yes, I'm a leftie.)
Meanwhile they also believe in contracting out. Some believe it's more efficient, some believe it's cheaper, some want to give profit to their mates, some believe it's part of the general fight against all-controlling extreme leftism.
Ok, so some companies bid for contracts. In doing so, they say they'll save money.
So at every level, people wanting to get promotion or even just keep their jobs aim to achieve that. But people at various levels realise there are problems, not least that there are more disabled people than they were told. Also, those cheating the system are the savvy ones and least likely to be caught or easily got rid of, so if you want to reduce numbers, you target the vulnerable ones.
The same happens with unemployment benefits and a range of benefits to reduce poverty for a range of reasons.
In any big organisation it can happen. It's strengthened by certain established memes in parts of the media. I'll use an analogy from unemployment benefits such as JSA, UC etc.
Young person has been out of work for ages. He says he doesn't want a job. What? Disgusting! You know there are lots of people like him because not only do you encounter them, perhaps in the supermarket, at the bus stop, online etc. but you read ab out people like that every day.
Actually, that young person does want a job, he just finds it less shaming to say he doesn't want a job than to say no one wants to employ him. That's in the context of a society where a politician, senior journalist, 'personality' or whatever would say the same thing. They didn't actually want to be minister for whatever because they have family commitments or have a passion for such-and-such a subject that's not a ministerial role. Ditto starring in that film or running that company or whatever.
So the sense that there are lots of cheats leads to ridiculous targets being set, but if you want promotion, are you sure you'll try to meet your targets by getting rid of the cheats not the vulnerable genuine claimants? And what if you can't find any real cheats? When I was a youngster we used to say the UBO (= jobcentre) is the only workplace where if you lose your job you still have to go into clock on the next day.