I think part of the issue is also that the negative impact of getting IT wrong is delayed, and often lands after your middle managers have moved on to other org

I think part of the issue is also that the negative impact of getting IT wrong is delayed, and often lands after your middle managers have moved on to other organisations, thus don't see the impact of cutting costs repeatedly. Since there's no visible problem (nothing catches fire) the day, week or month after cutting spend on IT, it's an unnecessary expense in the eyes of beancounters.