This is rational behavior. Voters cannot distinguish proactive spending from embezzlement. Politicians need to allow the problem to occur to prove that the money is actually needed.
In the case of covid - it would have happened everywhere else. So they would just have looked incredible le smart.
But with IT stuff, yeah it’s tough to justify - but maybe after things like this happen it will be easier. Sometimes you need a Pearl harbour to get stuff done!
Happens with military/infrastructure spending all the time - get a cheap initial quote and then get screwed long-term.
And with covid. Govs didn't have the courage to lock down early and fast / close borders and cost themselves a lot of money in the short term.