To play devils advocate: if the stock dramatically declines then the next people at the helm could buy back tons of the stock the more cash they have.

And to play devils advocate to that: Berkshire probably almost generates cash as fast as they would ever buy back stock.

They do buybacks pretty regularly, but obviously that’s true in aggregate.

I never said it was a mutual fund. But investors may still pull out money by selling stock. One area where typically this would come into play would be M&A (mostly A for BH). Unless you’re doing an all cash offer, there is an equity component to acquisitions. Lower BRK price would require you to offer up more equity, which is where cash is helpful. Your major investors are protected and you don’t lose out on opportunities.

Another place where normal corporations would be affected by stock price is when they want more liquidity for operations via debt. This doesn’t apply to BRK because they already have a massive stockpile of cash. But stock price is not that isolated from company operations if a lot of investors start pulling out money (by selling stock).