You should only prep for disaster if you want to survive a disaster, which is rare for more people. I live in earthquake country, and though I have not experienced anything larger than M4 in the past 28 years, stochastically we can expect a very large ($BILLIONS, with massive short term problems) quake at some point in Northern California in the next 50 years.

The items I describe fit on a single shelf (except the water; I have a water filter and a nearby stream, so I only keep a few liters on hand).

The stuff described would mostly fit in a backpack as it's all backpacking gear to begin with. The only thing that wouldn't would be 30 days of food and water which is probably overkill. A reasonable food supply would fit in a couple cubic feet and multiple redundant water purification options could fit in a pocket.

I'm just a backpacker though not a doomsday prepper, the stuff we carry isn't always appropriate for an emergency situation and is generally geared towards being very portable rather than robust/100% reliable.

Because there is an ongoing disaster?