Phantasy Star's Main Inspiration and Origin

What series in literature would you consider to be most similar or comparable to Phantasy Star (including all content from Master System till now)? Or what do you think was the primary inspiration for what we've known as Phantasy Star for 3 decades?

I've spent a lot of time contemplating this and found that Frank Herbert's Dune or, less so, Jack Vance's Dying Earth come as close to possible as an answer to this question but I'd like to know if anyone else has thought about this and what conclusion they came to.

Personally I kinda figured their source for inspiration for the original series was more "Dungeons and Dragons has a sweet love child with Buck Rogers" with a real nice anime art style to blend them together. This concept was really apparent in how the art for Phantasy Star 1 looked, where Phantasy Star 2 took a more sci fi approach.

The results I saw in Phantasy Star 2 and Phantasy Star 3 on the Genesis were amazing and led to a lot of late nights growing up, haha.