Earlier quoted context omitted.
It's definitely in the long term plans, but honestly in the five years I've been working on this, not one person has ever complained about that type of issue. And, the website looks amazing in fullscreen mode on a big monitor, way better than other sites I've seen (within my design limits).
Being a noxious frontend dev, the first thing I tested was whether you supported responsive. What I found was that you load a different site based on the viewport size (rather than dynamically changing on resize) which I think is a perfectly serviceable approach to this. Cool project!
It's so fast to build pages that building separate versions is much faster than building a single responsive WP page (for example).
Most of the time, both versions (or more if needed) are in a single Illustator doc and it's quite simple to maintain both at once.