It's usually the opposite. In a crash or time of hardship you want to spend more. Austerity in a downturn creates a virtuous cycle. That's the insight of Keynes and what got the world out of the Great Depression.

The austerity policy you're suggesting has been overwhelmingly found to have failed almost everywhere it's been tried. Cutting spending in a downturn creates slower growth, which makes it even harder to recover. The book in OP argues that austerity is not about recovery, it's about disciplining workers.

https://www.theguardian.com/commentisfree/2017/jul/07/imf-au...