Ok, so taking this at face (ish) value:
how do we get people who can work to work?
first, let’s think about what we mean by people who can work.
university students can work. We don’t make them stop studying and get full time jobs because as a whole for the economy we want people with high skill levels and so as a country we’ve made the decision they don’t have to work and the government will at least partially fund their studies.
back in the 60s and 70s it was generally accepted that women with small children didn’t need to be made to work. Since then many more women work and fewer men work.
see https://commonslibrary.parliament.uk/research-briefings/sn06838/#:~:text=The%20female%20employment%20rate%20was,compared%20with%2014%25%20of%20men.
lots of people who are retired can work. Most of them don’t want to and either have enough money coming in from private pensions and investments or state pensions etc that they don’t have to. Strictly speaking if you consider the state pension a benefit (which strictly speaking it is) this is by far the largest group of people on benefits who could be working but aren’t.
most of them don’t want to, and you’d have to really cut the state pension brutally to force some to go back because they need the money which would lose whichever government did it the next election.
then you are left with people of working age (18-67) who have not retired already and aren’t studying.
most of them have a job. The UK has a higher percentage of it’s population in work than any of the other European countries.
latest is 75.1%
https://researchbriefings.files.parliament.uk/documents/CBP-9366/CBP-9366.pdf
(remember most of that other 25% is students and early retired people).
the current focus on cutting benefits is not about getting people into work. The government have a financial problem in that benefits spending (which is about half state pension and a lot of the rest is benefits for people in work) is going up and tax take is going down because we are on the edge of a recession (Covid, Ukraine, etc).
pip is an in work benefit. People get it who work full time. UC is an in work benefit. People get it who work full time.
none of this has got anything to do with getting people into work, it’s just about cutting benefits. Cutting pip actually makes people less likely to work because it’ll pay for wheelchair adapted cars, taxis to work, etc.