Yes, that's generally how things shake out. This one seems like a personal project more than anything, but in my experience it's a miracle if you can convince a company that having separate mobile and desktop interfaces is advisable, much less getting buy-in for a fully scaling interface that adapts to screen size.

It's also difficult because outside of fully regular gridded interfaces (which, in all fairness, this site is), there are diminishing returns once you hit desktop size. And user flows can be interrupted or the false bottom effect (where there is content beyond the bottom of the screen, but the user doesn't realize it's there because what they can see cleanly cuts off at the bottom of the screen) can come into play if an interface is designed to scale with screen size.