Final answer:
The potential substitute for the book title "Dow 36,000" could be "The Sum of the Market Caps of All 30 Dow Jones Members Will Triple".
Step-by-step explanation:
The potential substitute for the book title "Dow 36,000" could be "The Sum of the Market Caps of All 30 Dow Jones Members Will Triple". This is because the Dow Jones Industrial Average Index represents the market capitalization-weighted average of 30 large companies listed on the New York Stock Exchange. If the sum of the market caps of all the companies in the index tripled, it would align with the idea of the Dow Jones reaching 36,000 points.