You clearly know nothing about PIP assessments.
If there is a Doctors letter saying that someone has lost all 4 limbs to Sepsis for example, or a person has a severely disabling condition why does this need a face to face assessment for someone with complex needs who can't even walk or talk for example. Are you saying a Dr can't be trusted and someone else needs to be paid to count how many limbs someone has left.
We'd waste less money if we stopped regularly assessing people to see if their limbs had grown back and also accepted that lifelong conditions don't change. There is a requirement to tell DWP if something changes and your limbs magically reappear.
Assessments are almost always done by private companies that make profit out of this. This means that the taxpayer isn't paying DWP staff to do the work at cost we are paying huge private companies to do this work for profit - so it costs more because they make profit out of this.
The private companies are incentivised to turn down applications.
You may think it's good to deny more claims as it 'saves money', but the truth is that claims that are turned down can be appealed. The majority of appeals find that the claim should have been granted and the Assessor was wrong to deny the claim.
When a claim is appealed the DWP has to do more work and the courts get involved to hold tribunals to hear the appeals - this costs a lot of money.
People are paid PIP because they are severely disabled and for some so that they can get care they need to help them stay in work, or get in to work. People on PIP who work pay tax just like the rest of us and so they are also contributing to the cost. Without PIP payments the cost of disability would be very much higher.
You will find it very hard to find someone who is disabled that wouldn't gladly swap their meagre PIP payments for an able body.
Everything to do with disability costs more - wheelchairs and car adaptations are very expensive. PIP allows you to have a car lease (with an upfront cash payment you pay yourself) or a wheelchair - not both and the NHS does not provide wheelchairs (Physio, Orthotics, Braces, Hoists, Commodes...) to everyone that needs them.
I hope you are never in a car accident that is no fault of your own but leaves you with a loss of limb(s) or you have Sepsis that means you lose all four limbs or you get a terrible disease that leaves you with a permanent disability. Because then you too will be the object of hatred and ridicule for getting some small financial support for the enormous costs you face dealing with the impact of your disability and the total lack of care and support from the NHS and 'the council' for an awful lot of conditions and disabilities.
You may even have to give up going to your favourite pub, restaurant, sports venue, concerts... because you can't get access or there are so few accessible tickets you missed out. At least you won't get left in a burning building anymore as a child campaigned to get this changed after he was left alone in a school that was on fire as there was no evacuation plan for a child in a wheelchair.