All awards by law have to have reviews so that change both good/bad can be taken into account and to be fair that was not always happening before with DLA.
Best award now is ongoing but that can still be reviewed at anytime
Problem being over the last 10yrs the unaccountable DWP continues to move the ESA/PIP award qualifying goal posts so as to be seen to be meeting the new targets that are set by No 10 ( fact is many of those denied benefits are reinstated at appeal court stage)
Their target being simply to deny as many disabled people of as much needed support as they can even if that means spending more ££ss than before to do so.
They have tied their selves in knots, for example ESA reviews from 2016 are only now starting to be looked at ( same Dept people as PIP different hat)
I have lost count of how many I have helped over the last 10 yrs and steered through this minefield of a system
I too get worked up over stuff like this and I could also go on and on, but I best stop and keep it short.
Again this is also just my opinion