No that's just one component as to why austerity failed, austerity can work if done correctly, unfortunately it appears the UK didn't do it effectively, but that's not to say it didn't work to a degree.
Economics is very complex, we could be here all year discussing it.
You think that by magically printing more money that will fix everything with no downsides. By just printing more money it will impact the rate of inflation and so a balancing act must be done.
There are many financial advisors to the UK government and Bank of England and the decisions made by government regarding the economy are largely done with their input, and I'm pretty certain they know a lot more than anyone on a DIY forum
I know how money is created, you can Google it if you can't understand it, I would write it but I'll be on here longer than I want to be, and what's the point of reinventing the wheel if the info is easily at hand.