It is not necessarily incorrect, but it isn't right either.
Final Fantasy VIII's "planet" has already developed the technology to be able to travel to Space, which is obviously a very big leap. However, Final Fantasy XIII has seen more of a technological advancement. The leap of space-travel was not made simply because it is not relevant.
By architecture, technology and society in and of itself, "Cocoon" is the most advanced planet in the entire series.
^ Yes, Cocoon had full availability of resources and protection that allowed it to develop into a highly advanced and capitalist world.
Other than that, you could always consider the "Dream Zanarkand", but alas the storylines throughout X and X-2 never truly delve very deep into that aspect and thus never show you where the limits of Zanarkand's technological advancements were prior to Sin's advent.
I hope you found that informative~!
I went ahead and cut&copied this one down here - do me a favor and please try to keep things organized, people. If you have something to comment about a certain part of someone's post, do like the poster did between my post over there, use the "^^" sign, and possibly put it in bold to differentiate.
Esthar is probably the most advancet one even for ff8