How does one define "small minority" and "most people didn't like the game"? These both seem highly ignorant, not to mention arrogant, to what could possibly be a very large majority. Remember, it has been established that fans of a series who do hate a specific movie or game feel the bigger need to complain about it, often times to the point of overshadowing the majority of people who liked it because their responses were louder.
Let's also remember that over a million copies of the game was sold at launch and that the game was given positive reviews from most reviewers. To say that most people hated it would be untrue, because it wouldn't have had such a reception if it was largely disliked. You can go on a vast majority of sites that have reviewers and ratings from casual fans and you'll find that the majority are positive about the game.
So, while you can say a large amount of people didn't like it, obviously there was enough of a response that it got a sequel. Square Enix said they would do a sequel only if there was enough fan demand and several months later Final Fantasy XIII-2 was announced. If the audience wasn't there, then it wouldn't have happened.
As well, Kitase has said before that they would only do a Final Fantasy VII remake if everyone involved in the production came back for it. Considering that many of them are working on different games and many might have left the company, this would be very hard to do.