Most mainstream economists think it's good for a government to increase deficit spending temporarily during a recession because it helps prevent deeper recessions that cause long-term impairment of the tax base. If you let half the auto industry fail, for example, it may take a long time for your tax base to recover and start generating taxable income again.

After the crisis, there was bipartisan agreement that the deficit needed to be reduced, but the disagreement was on how. Obama was willing to cut spending but also wanted to increase taxes on higher income households, while the Republicans in Congress drew a hard line against any tax increases and wanted deeper spending cuts. In the end, they reached bipartisan bills, including the American Taxpayer Relief Act of 2012.

The debt ceiling brinksmanship was political theater. Republicans used the threat of defaulting on US debt in order to extract concessions from Democrats without having to agree to any policy demands. Congress passed laws with required spending every year and no one has the legal authority to not spend it. If Congress really cared about reducing the deficit, they wouldn't pass spending bills that required deficit spending.

As for increasing debt in the 2010s, I think it was viewed as a potential long-term problem but sustainable because interest rates were quite low. When inflation was at 2% and interest is at 2%, the US government was able to borrow money at 0% in real terms. Government spending on roads, airports, and even marginally productive projects that increase economic growth could be viewed as rational.

I think the US and world got complacent during the low interest rate era, and eventually realized deficit-spending in a low-rate environment boosted economic growth more than expected. The US doubled down on this by passing the 2018 Tax Cut and Jobs Act, which reduced taxes significantly without cutting spending concurrently, which created large deficits even during periods of economic growth.

The problem now is interest rates have gone up substantially, so debt servicing is going to become a much bigger burden. I don't think it's politically possible to reduce the deficit through spending cuts alone. The annual deficit is greater than the entire US defense budget and Medicaid combined.

Unless we suddenly get a burst of growth from AI that will increase our tax base, (which I think a lot of politicians are counting on), a long-term fix will require increased taxes (which will slow economic growth at least somewhat) and reduced spending (in particular lowering healthcare expenses, which are still rising at an unsustainable rate).