Harry Thompson
You make several fallacious inferences. While no one can predict with certainty the exact amounts of future aggregates, one can with fairly good certainty, identify trends. When one considers all types of investment vehicles, as trends, the stock market outperforms all others over the long term. Now, any particular investment return is particular to those doing the investing. But pension funds, that I have cited as models, generally have as their investment goals preservation of capital while achieving growth. As a consequence, their selection of equities contains fewer equities which might be considered volatile. the amount of each would be determined by the fund's managers, which are different for each fund. Some funds have out-performed the market average, others were a bit under. But virtually every fund outperformed fixed income investments over the long term. So let us understand that in making these predictions, you must consider trends, not actual performance, and there is indeed sufficient data available to chart trends over the long term.
Not entirely; but considering actuarial factors, such as the length of a working career during which an individual makes contributions towards a retirement fund, and estimated life spans after retirement, 30 year trends are far more valid.
Alan