Vasteras has collected a lot of debts, the Seven Kingdoms budget has long been unable to cope with the costs and default close.
In the fantastic reality created by writer George Martin, there are many fictions: dragons, falconers, White Walkers. At the same time, the Martinov world works according to the same laws as the real world. The main attention of readers and spectators is focused on the struggle for the Iron Throne. At the same time, in the second plan, the main means by which the struggle is fought is money.
The financial condition of the Seven Kingdoms of Westeros is unenviable. The monarchy spent a lot of money, while incomes did not allow such costs. Moreover, the funds were spent on feasts and chivalric tournaments, and not invested in long-term growth - infrastructure construction, for example.
As a result,
the kingdom has accumulated a great debt: three million gold dragons in front of the Lannister family, two million in front of the Iron Bank, and another one million before the Church of the Seven. Revenues allow you to pay only interest on debt. A big debt is not a disaster if the economy grows. The growth of public spending can strengthen GDP if funds are spent on infrastructure construction, public goods and capital investments. However, as already mentioned, the kings took more care of entertainment.
In dire times, calls for extreme measures must be heard. Sometimes the only way out of brutal debt and lack of ideas (other than inflation of course) is war. Taking over other nations and their resources. Or the Kingdom could just absolutely rape their own people for every penny they have, but of course, they'd weaken themselves eventually to the point where it'd be beyond fucked. Probably the royalty would be targeted by the pleb populace. It's funny how screwing around financially can absolutely mess with everything you have in the end. Long-term thinking must be employed.
Civil wars are extremely costly though, there's not muchh resources to gain while you're diving up everything in your nation/kingdom. After an extended period of time, the morale goes down and people just abandon everything entirely. Wars aren't a good solution, but they are a solution where in some cases there's not any other better routes to take. Of course maybe that's why we have less wars now than ever before, but still.. they haven't fully gone away.