So 90% of the time I hear these horror stories it's a test/dev account where deleting everything is preferable to getting a bill. I also don't understand why e

So 90% of the time I hear these horror stories it's a test/dev account where deleting everything is preferable to getting a bill. I also don't understand why everyone is assuming "if I hit threshold X do A, if I hit threshold Y do B" where A and B are some combination of shutting down and deleting resources, is as difficult as solving NP complete.