Note that the differences between Berkshire A and B aren't that great. B's have about 1/6 the relative voting rights per dollar of value. I used to look at arbitraging the A shares into B shares when the relative values were attractive, and voting rights never mattered because I wanted the guy running it to have that power.
But maybe that's wrong. I like what the S&P is doing here and maybe they should drop the hammer on GOOG and BRK too. And I say this as someone who has about 2/3s of my net worth in BRK.
In fairness to Berkshire, the A and B shares are both traded on exchanges. If the voting rights are important to you, you can just buy the A shares. In theory, if you had a metric ton of money, you could take control of the company just by buying shares there.
In Snap, you can't go on exchange and go buy the voting shares. They're held by insiders who won't sell at anywhere near the price of the non-voting shares.
And in fact S&P had to change its methodology for the S&P 500 a few years ago to allow for the two publicly traded Google share classes (A and C) to be included in the index.
It seems like an arbitrary criterion and God forbid Google starts investing into future growth a la Amazon, but you're right, as long as the profits are rolling in, the interests are aligned. When the music stops, it's yet another GRPN or ZNGA.
Although the immediate reason BRK/B ended up in the S&P 500 was because they acquired BNI (Burlington Northern, a railroad company) for stock in 2010. But fair enough that it wasn't in there beforehand and is still around now. I don't remember why, probably some other S&P decision about the big-numbered, less liquid BRK/As.
Also, BRK/A shares are quite expensive but you still get Buffett's shareholder reports with a share of BRK/B. I'm sure you could find them either way, but hey. Interesting reading is a nice fringe benefit.
No, they are also disallowed from being added to the index, but are being grandfathered in.