collapse of the old society

Yes and no. Basically collapse scenarios fall into buckets. One bucket has all the scenarios with rapid collapse, e.g. nuclear war. The other is slow Collapse, e.g. climate change. The preparation for every scenario relies on broad self-sufficiency, but if you’re looking at climate change, your personal farm might need more water and a way to control soil temperatures. For nuclear war, your whole enterprise needs to be in a bunker away from major targets. Since the exact collapse scenario is unknown so far, the move if you can afford it is a hybrid approach and do both. Excess food is never a bad thing; indeed you can attract workers with a promise of wages and free food to work the farm on the surface while maintaining your non-perishable stockpile and food production in a massive bunker that you only let family members into.

Ultimately, though, you’re still fighting the problem of inevitability. Even if you and your family somehow escape dying from nuclear war, what will your kids do? There will be no doctors, no water sanitation engineers, nobody to rebuild what was. In essence, a billionaire and family might outlive the collapse, but they’ll be either stuck in their Vault or they’ll inherit an uninhabitable planet.