The point is that then and now - cigar butts, value stocks, moats, whatever - MO had been right there as an obvious stellar buy, and for ethical reasons Berkshire had deliberately and steadily foregone investing in it.

I think it's not JUST ethical reasons. I think WEB and Munger prefer to invest in things that provide positive results, for the investment AND for the world. So, for example, they would never invest in gold or in cryptocurrencies, because there is no net positive from those, they are simply mechanisms to transfer money from one pocket to another, with nothing real earned. Remember a few decades ago in WEBs letter the parable about the big block of all the world's gold on one side, and a bunch of large companies on the other side that produced very useful stuff and produced earnings every year. Now, some people would consider railroads (or utilities) to be polluting "evils" in the world, and while that may be true to some extent, there is a substantial net positive to the world in that they move goods to where they are needed (or provide power where needed, etc). Now, in today's world we know a little more about health and nutrition, so maybe candy has no net positive effect on the world, but people do enjoy it (even though there is no positive nutritional value whatsoever). Luckily the candy business is so small that it isn't of great concern to the overall ethos of Berkshire. And I think WEB is too old to change his ways, he will eat junk food and drink full-sugared Coke until he dies. Maybe the next guy (Able) will discard some businesses that no longer provide any true positive to the world.