Suppose you buy a perpetuity, granting $X every year. After 100 years, you'll have 100 times $X more dollars, but you will be worth exactly the same as you were worth before the perpetuity. (This assumes that the market correctly prices the perpetuity so that the expected value of purchasing it is $0).
EDIT:
I'm not talking about "profit" because it's not really a super useful concept here. Having a larger quantity of dollar bills after a period of time does not mean that I've got more value. Trivially, if I have $100 in 1950, and $101 in 2016, I have made a "profit" of $1 but lost a substantial amount in real terms.
I should cite sources and use correct terminology.
Wikipedia provides the following [0]
> The dividend discount model (DDM) is a method of valuing a company's stock price based on the theory that its stock is worth the sum of all of its future dividend payments, discounted back to their present value.[1] In other words, it is used to value stocks based on the net present value of the future dividends.
It's a nice Econ lecture but markets do not actually behave by a manner of collective estimate of dfcf. I would say it's more accurately described as a random walk with an upward inflationary bias.
The stock will cost a fair market-clearing price for its expected return, risk-adjusted. But often a stock, or a perpetuity, is a good purchase for one or other market participant - no different from a loaf of bread bought at a fair market-clearing price.
One can say that this "risk premium" actually reflects the expectation that things don't go as well as expected. But the fact is that in the aggregate and in the long term equity investors are still doing "better than expected" and there is no agreement on why it is so (this has been called the "equity premium puzzle").
I believe you would agree with me that a company could exceed expectations while at the same time not growing (by giving out a bigger dividend, or buying up its own shares with its profits).
But that's not really what you're doing when you invest in an S&P index fund, right?
The stock price doesn't just reflect the amount of money the company has. The stock price reflects the "fully loaded" expected value of that stock. That means it prices in ALL expectations.
If the company you buy performs exactly as expected, then you don't actually make any money because you paid the price that reflected those expectations, so whatever dividends the company issues will only compensate you for the premium you paid. So the stock has to outperform expectations before it's worth buying.
The "expected value" of the company actually discounts dividends and the like, because the value of money in the future is less than the value of money today.
There's an amusing side point to this, which is that a perpetual annuity actually has a finite value [1].
[1] https://en.wikipedia.org/wiki/Perpetuity