What am I missing?
I think the idea is that he doesn't want to return cash while there are still good investments and made the B shares available for those who need liquidity.
In fact it seems like voting is actually not that important, since if you didn’t trust Buffett to run the company for you, you would be investing in something else.
In practice the rise of stuff like cryptocurrencies and NFTs shows that this theory is only partially true, and perhaps there is some nonzero lift on the price due to people just buying it because they think the company is cool or whatever.
You don’t need to buy BRK.A to benefit from Buffett’s financial acumen. You only need to buy BRK.A if you want to say you own BRK.A.
Also, the harder it is to transact a stock (and a price over $400,000 makes it hard), the less efficient price discovery is.
If you can construct a portfolio that exposes you to only that specific event (and not something like the further increases in value until that point -- seems difficult but maybe possible?) you might learn the probability of it happening at various points in time, through its price!
Maybe you'll find that portfolio seriously underpriced (another comment gave some potential reasons why it would be) in which case there's money to be made.
You'd do that by going long in all stocks that Berkshire owns, and short Berkshire itself. The problem with that is that Berkshire also has a bunch of non-listed subsidiaries you can't buy.
https://www.cnbc.com/2021/05/03/who-is-greg-abel-warren-buff...
There is a booked called "the millionaire next door" that is a good read.