Got you added TCJr, thanks!
Yep, detectorists tend to be pretty solitary in general, I think. Even the Friendly Forum member numbers bear that out - over 53,000 members listed, but only 174 participate in the map! Lots of those members are inactive, but there are also plenty who aren’t interested in joining up with others, find other ways to meet hunting partners, or don’t even know the map exists - heck, some flat out don’t like the idea of map, which is fine, too!
Hopefully it helps you out to find someone to hunt with. I think the map can be particularly helpful to more easily find a member who is willing to join up for a hunt when visiting or travel through an area that’s new to you.