Here is the definitive breakdown of why this specific game does not exist on the PS2, and what you might be finding instead.

The short answer is no. Marvel vs. Capcom 3 was never officially ported to the PlayStation 2. This article explores why a PS2 version doesn't exist, the limitations of the platform, the reality of "ROMs" for newer games, and the best ways to actually play this masterpiece today. 1. Why There is No Official Marvel vs. Capcom 3 PS2 ROM