They are! The problem is, what are you going to do about it, when spending less / taxing more leads to you getting voted out?
Humans in general are near-sighted, where gratification today is worth more than the pain of tomorrow. That's why reducing usage of fossil fuels (and seriously addressing climate change as a consequence) is not something governments want to do, and why borrowing money to create jobs & develop the country & stimulate the economy is so popular. It's the people of the future paying for it, and by the time that debt actually needs to be paid, it's no longer a problem for the politicians of today.
Edit to add: See Harris and Trump would both make the national debt worse which also describes this issue. As of 2024, both presidential candidates describe policies that add several trillion dollars to the national debt. And yet they must, because they need policies that are "customized to please each candidate's desired constituencies" to get elected. The last two paragraphs put it in stark terms:
No politician can get elected by vowing to reform retiree programs — remember when President George W. Bush tried to reform Social Security back in the day? That's especially true now that mass disinformation allows cranks and scaremongers to transmogrify any reasonable-sounding plan into Armageddon.
Many voters say they’re worried about the imposing size of the national debt, but most people want somebody else to pay to fix it. The inevitable result is that we’ll all end up paying, and it will be a lot more than necessary.