AdrianC, you are putting the events on their head.
It started with these two posts:

LongTermBRK: What do you think happens to SPY in panic and turmoil?
AdrianC: SPY falls 50%+, and Berkshire falls 50%+. They did in the dotcom era

This era then was defined more precisely by LongTermBRK: The dotcom era collapse, beginning 1 Q 2000
Your reply: But Berkshire did have a near 50% drawdown in that era.
stockcharts.com: PerfCharts | StockCharts.com
It recovered in about 3 1/2 years.

Please have a look at your own chart. It was exactly the other way around. Berkshire went down BEFORE the dotcom collapse, during the years every High-tech stock went up. I know this so well (and your chart shows it too) because at the very lowest day I bought my first Berkshire shares (thanks to a Jim Cramer yelling that very day: "Regarding Berkshire there is only one thing to do: Sell! Sell! Sell!". Thank you, Jim!).

Berkshire went heavily down not in the era of the bursting of the dotcom bubble.
It went down in the era before, the dotcom hype era.
And went up in the era of the bursting of the dotcom bubble.