Looking at pip as a whole,
there’s two arguments going on here which to some extent aren’t the same.
first, that benefits need to be cut. Half of all money paid out on benefits goes on pension. So there are limits on how much you can save by cutting other stuff. Hence the focus on the triple lock.
the obvious way to cut pip is to means test it, but my suspicion would be that most claimants are low income so it wouldn’t save a lot. You’d need to also do a bit like child benefit and allow people to get pip but not get the money as it is a passport for lots of other things - blue badge, carers tickets etc.
again, for quite a few claimants they have social packages of care anyway. I’m disabled and many of the people I have met at disability support groups are living in council provided adapted homes with care packages of people going in regularly. The cost to the state of the care packages is really high and cutting pip will just mean that they still need overnight care/wheelchair/etc so they’ll “contribute” less to the care package but it’ll still be funded.
so no saving overall. But it’ll come out of the benefits bill and go into the social care bill.
separately, the idea that pip should be partially a support package is not a bad idea. The nhs doesn’t really provide wheelchairs anymore and it’s up to you as a disabled person to buy your own aids with very little advice, and finding exercise classes etc that are accessible is really really hard.
so… realistically they’ll probably means test it but it won’t save much.