I believe that in about 2-4 years hardtails will gain more market share as those buying fully suspended gravel bikes will 1) suffer from n+1 and 2) realize that as they continue to push the limits of their gravel bikes on trails, will want the benefits of a mountain bike. My first bike as an adult was a hardtail Kona that I rode everywhere. I had a second wheelset with 32mm slicks that I used as I started getting into road riding. Sure it was a slog on those road only rides, but it killed in the woods! And my skills were not very good...but the bike made up for it. I miss that Kona.