It is never going to be worthwhile for a personal investor to attempt to beat the market.
That statement looks very iffy to me.
Beating the market's a zero sum game
No, not in general. Some markets are more or less zero-sum games (e.g. futures), some are not (e.g. equities).
By my reading, your reply about the structure of futures and equities markets equivocates on the word "market". To me, the phrase "beating the market" means getting a higher expected return than average, which I think is zero-sum. Do you not think "beating the market" is zero-sum?
To me, the phrase "beating the market" means getting a higher expected return than average
Oh, and by the way, that's not what this phrase means to most people. Its standard meaning is "achieve a return higher than that produced by buying and holding an portfolio of all assets in the given market".
For example, let's say that S&P500 returned 10% in year 20XX. This means that a portfolio of 500 stocks that constitute the S&P500 index has produced a 10% return for this year. Notably, this does NOT mean that the average return of all people who invested in some way in the US equity market is 10%.
P/S/A: There are single sentences which can create life-changing amounts of difference.