I have no idea. I didn't pay attention to how much I lost, so I also didn't pay attention to how quickly/slowly it came back. OTOH, we were able to buy our retirement condo out of foreclosure, for about $100K off. So overall, we are better off as a result, because we didn't sell off when the crash hit.
I really think there are two separate issues here: (1) how much you need as a safety cushion if you are still working; and (2) how much cash you need on-hand when you retire to ride things out.
On (1), I do think people underestimate how interrelated the different markets are. In the first tech crash, DH lost his job when his plant shut down; we then had to move for him to find a new job but couldn't sell our house, because the tech crash had put a lot of people on the street, and so the real estate market crashed, too. I have always been a big fan of low mandatory expenses, living on one income, and having a big EF, but that couple of years persuaded DH that I wasn't crazy after all.
On (2), there are different ways to handle it. Some people set an asset allocation (80/20, 60/40), and stick with it; some people start more aggressive and go more conservative over time; some people do it the other way. Me, I plan to have about 3-5 years' planned expenses in CDs or individual bonds, a side fund for capital costs (e.g., new roof, new car), and everything else 100% in stocks. I also have a generous budget, so there is a lot I can cut back on for a couple of years if the market stays down longer than I thought.
I don't know which approach will be the most profitable. But I don't need the "best" -- really, why do I care if my heirs inherit a little more or little less?) I just need to make sure that I have a plan that maximizes my chances of not running out of money. Since my two biggest risks are (a) inflation risk and (b) having to sell low to cover costs, this approach makes me feel the most comfortable that I can navigate those two risks successfully.