Why all the Final Fantasy Sequels/Spinoffs?

RPGFan has an interview with Square Enix President Youichi Wada in which he says:

Wada disputed his interview partner's suggestion that Square Enix had recently released a lot of sequels and remakes, by saying both sequels to existing IPs and original games were necessary to grow the business. He explained 60% of
Square Enix's profits came from existing IPs, whereas 40% were generated by original titles. He also refuted the common held perception that Square Enix was overly dependent on its flagship Final Fantasy and Dragon Quest series, saying they accounted for less than 50% of the profit. And while the company was trying to further reduce its dependence on these franchises, he remarked people kept asking about new installments of either series. (Full Story)

The Final Fantasy spin offs tend to fall into the great (X-2) to the downright crappy (Dirge of Cerberus) Maybe they should focus their time on Final Fantasy XIII, we'd really like to see it before 2034!