In all honesty, I think that was SE's initial intent. People who played XI would have an interest in XIV, therefore they'd switch over. It would explain XI's current trend of increased level caps every few months and new (from what I understand,) easier content.
However, because of FFXIV's poor reception, you won't see XI go anywhere for a while, at least until/if XIV can gain interest from fans.
This is my sig; Enjoy.
FFXIV: Tom Carroll - Excalibur
FC: Sitzkireg (www.sitzkrieg.guildwork.com)