Why is everyone taking this FFX-FF7 "link" so seriously?
Because, like it or not, Kitase and Nojima have said the connection exists in the FFX and X-2 Ultimania books.
Maybe what's really going on is that Kitase and Nojima are just out of ideas and are hoping some forumgoer will come up with some sort of plot to use to milk the Final Fantasy cow even more.