“If the apocalypse is a financial apocalypse a bunker will be almost useless. “
The military has them, and some civilians have them done right.
Properly outfitted, you can maintain a decent environment for a year or longer in relative comfort - with power, water, hot showers, clean clothes, the whole shebang.
The scenarios can be pretty far fetched - EMP, Bird Flu/pandemic, financial collapse/chaos, nuclear fallout - but it IS possible to mitigate them, or some of them, if you want to do it.
It can be done - but maintaining a low profile in your chosen environment is the tough part.
You’d have to come out eventually.