I wish that was a rhetorical question and I was about to propose an answer. Sadly I’m not. At best we have an illusion of permanence, but our business lives can change in an instant. Usually without us being involved in the decision!
There are the obvious examples. The other cast and crew on Rosanne had their livelihood jerked out from below, through no fault of their own.
The production crew on Parts Unknown who face a very uncertain future, as do many at Zero Point Zero Productions.
One acquaintance lost business and home in quick succession and has left LA. Another had a decent, well paying job at a major studio until downsizing eliminated the position. An unfortunate bout of ill health without the cover of employer insurance, and within 2 years he was effectively homeless. Another laid off from another studio job is finding a home for their many talents and abilities.
How do we prepare?