I took a graduate level measure-theoretic probability theory class. The professor had this rant about how "buy low, sell high" was a bad idea, it's all about how long you stay in the market. He had a mathematical proof that, if I recall correctly, only held if the random process is monotonically increasing in expectation, which of course is not guaranteed.

trading, frictional costs, and the asymmetric psychology of selling winners and riding losers are a better explanation for why buy low, sell high is a bad heuristic to aspire to.

This is a key point. Especially if we actually start doing something about CO2 emissions, which will mean reducing energy consumption for the next couple of decades. Stock market growth has historically been tightly linked with energy consumption growth.

While the point of probability of staying low holds, I don't think there is a tight coupling with the energy consumption. Surely, nature (business ecosystem) will find a way for growth driver even without energy density increase.

I think nature's growth will be like 1% or less, certainly not the stock market growth people are used to. To me, it is obvious there is a tight coupling: energy does work instead of humans/animals, thus allowing more productivity. When you look at a construction site it's just human directed diesel-energy (with some chemical energy in the concrete).

Much of the developed world is transitioning to a service economy that relies less on the fossil fuels, but it still relies on the inputs that do (agriculture, electronics, offshore manufacturing). And we've set up the economy around fuel consumption: long commutes from suburbia, inefficient houses, processed and packaged foods, etc. And what about the travel industry: burning fossil fuels for no productivity (just realized it acts as a mop for the excess capital).

If we're lucky, we can use the fossil energy to bootstrap the renewable energy, then we can eat farmed foods, drive electric cars, and work on computers remotely. But there just won't be the energy to drive the economy the way cheap energy does.

+1. it took about 3.5 decades to return to the levels of the pre-'29 crash. bear markets can indeed drag for decades. stockbroker happy-talk tends to gloss over these facts.

If you had reinvested your dividends, you'd have gotten your money back by the end of the war (and you'd only have lost 1 or 2% approximately six years later).

35 years later you would have an annual return (inflation adjusted) of 6% (6.5 times as much as you put in).

And this is somebody who invested in the absolute peak of the market in 1929, and then saw the worst crash in history, followed by the worst war in history.

Past performance is not a guarantee of future results.

Markets can grind lower and lower for decades, each new low triggering bargain hunters to buy, only to drop more.

Sure, but that can happen if:

1) Shares were massively overvalued compared to their yields. E.g. if P/E ratios were 50:1 then I wouldn't buy the market

2) There's a fundamental issue in the economy. Plague, war, asteroid, climate change. Whatever the issue, you probably have bigger things to worry about than your retirement fund, and you have no better bets to place

The stock market is just made up of businesses. Businesses make money. Owning part of a business gives you a return. There's no magic to it, no massive extrapolation based solely on past performance. If you think there's a decent chance businesses aren't making money, then you ought to become a prepper.

Did you exclude or include dividends in that assessment?

If you reinvested your dividends you'd be up 25% without taking into account inflation, or down a total of 1.5% if you took into account inflation. Not ideal, but not much different than when you started.

I personally buy an all-world tracker, the Nikkei is an outlier. There could be issues that affect the global economy long term, but if that were the case, I'd have other things to worry about in addition to my investments.