They're probably equipped with enough food stores to last their lifetimes. That's what I'd be equipped with.
Ways to make fresh water and food, ways to generate electricity, and as we can all guess, an enormous stockpile of toilet paper.
Ways to make fresh water and food, ways to generate electricity, and as we can all guess, an enormous stockpile of toilet paper.
In the face of true societal collapse, lifetime supply of food is more of a problem than it is a solution.
If I'm too old to defend my food, either all the raiders have starved, or they've started farming.
A nice food forest would probably be the best option. Camouflaged to most laypeople who can't identify plants. Only collectable some parts of the year. Attracts wildlife.
People in large cities have different problem sets than people in remote areas. I don't lock my doors, either. People don't wander by. I'm bordered by bluffs and wilderness.
Food stores can be buried etc. I have buried things on my property in the past for a couple of years, came out unchanged.
Also I just think you haven't thought through many of the problems you presented, most are easily solved.
24h guard? No, I'll make good use of zoneminder, moron detection, loud alarms, and a lot of cameras.
I mean I already have that and I'm not wealthy, for an American.
It's not hard to hide a place underground or in a remote wilderness when you have a lot of money.
Or just somewhere easily defensible, with one path up, that requires heavy equipment to alter.
As a billionaire, I believe I would have built some fortified positions to fire from without much chance of being hit myself.
Also I doubt I'll have any kind of obvious entrance to wherever I am.
Even on my own real-life property (I'm not a billionaire), I'm not just going to be like...in the living room. In an end-of-the-world scenario, I'll be camping discreetly somewhere on my own property, which is mostly a hardwood forest with a pretty dense understory. It wouldn't be any more inviting than hundreds of thousands of similar acres, so security through obscurity is pretty good.
I'll have access to all the tools I need, a house, my own water source. I'm not particularly likely to survive on my own permanently, but I think I've got a shot to wait out a storm for a year or two.