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).
Your competition in the stock market is not your neighbor -- it's a family office managing $200 million.
First, there are many more markets than just the (US) stock market.
Second, if you want to go in that direction, that family office is small fry. The behemoths of the market are institutional money managers -- pension funds, for example. They, notably, have different success criteria and different incentives than individual investors.
Third, I don't quite understand in which sense that family office is "competition".
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?
P/S/A: There are single sentences which can create life-changing amounts of difference.