Sales: Why did TP soar and SS flop?

[atma998]

It's all about the first iteration of an established franchise on a new generation of console vs. the second one.

In other words, the first game of a franchise which is in its maturity stage will always sell more than a sequel on the same generation of console, especially if the game is released late in the generation. Sure, there are some exceptions here and there but mainly the sales are following this trend.

For example:

The Legend of Zelda: Ocarina of Time (7.60M) vs. Majora's Mask (3.36M)
Final Fantasy X (8.05M) vs. Final Fantasy XII (5.95M)
Final Fantasy VII (9.72M) vs. Final Fantasy IX (5.30M)
Metal Gear Solid 2 (6.05M) vs. Metal Gear Solid 3 (4.23M)
Gran Turismo 3 (14.88M) vs. Gran Turismo 4 (11.36M)
Super Mario Galaxy (10.12M) vs. Super Mario Galaxy 2 (6.75M)
Mario Party 4 (2.47M) vs. Mario Party 7 (1.57M)
Pokémon Diamond / Pearl (17.98M) vs. Pokémon Black / White (13.99M)

This is why when you're comparing sales of one of these game to its predecessor, you always have to compare it to the first iteration on the last generation of console rather than simply comparing it to the previous release of that franchise to see if it performs well.