No way Congress will fully prepare for any of those events.
Part of the reason is actually reasonable. You measure risk by multiplying "harm if an event occurs" times "probability of the event occurring". If an event has a 50% economic harm, and a 50% chance of occurring, one can reasonably argue that the government should prepare for a 25% overall harm (.5 x .5 = .25). Repeat this for every harm. Then evaluate how to spend your risk mitigation budget based on those calculations. Granted, the closer the probability becomes 100% as time marches on, the more seriously the government should prepare. but, regarding a pandemic, it seems to happen once every 100-200 years, so it is easy for a 2-year Congress to agree to handle that next session.
And, of course, Congress would rather spend money on entitlements, and only fund risk mitigation at a minimal "see we are doing something photo-op opportunity" level. So, like the deficit, being unprepared for these types of events is inevitable, and therefore always the perfect political storm. Put 1M masks in storage, have a photo-op...then, when we need 100M masks, just blame the other guy. (And, interestingly, 1M masks might have been a reasonable amount to have in storage...no one ever talks about the reasonable expected probability of the dice coming up snake eyes after snake eyes are already rolled.)