You arent making any sense. Look at the numbers, please.

Since it's release, Final Fantasy VII sold 8 million copies.
Since it's release, Final Fantasy VIII sold 6 million copies.
8 is bigger than 6, VII sold more.
When VIII was first released, it set records for selling so quickly. It did not, however, break VII's gross sales records, as it clearly states above.

This really isnt that hard to understand, is it?

Also, a game or movie selling well on it's release has nothing to do with the quality of the game. It has to do with name recognition (which VII built in this country) and advertising. After it's been out for a few weeks, then news regarding it's quality spreads through the community and boosts sales. That's why word of mouth becomes important for a film, but only after it's been released.