FFT is simply not as popular as the numbered FF's, so most people are not familiar with the in-jokes and references because they haven't played the game. FFT connects directly (and retroactively) to FFVII and FFXII connects (again retroactively) to FFT. And as you said, the references are just that: references.

To have all the FF's happen on the same planet would require major continental upheaval (on par with FFVI's), which is far-fetched. At any rate I think the FFT-FVII linkage suggests that they happen on separate worlds that may coexist at the same time.