I think it's mostly because the Atlantis was designed in the pre-DTT days and Grant et al are probably loathe to mess with one of their most consistent sellers, a bike they have said they intend to keep making "forever."
In one of the most recent readers Grant did have a short blurb about "retrofitting" a DTT to an (his?) Atlantis by strapping a mitered dowel between the seat and headtubes. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To view this discussion on the web visit https://groups.google.com/d/msg/rbw-owners-bunch/-/EJqaHypW2UMJ. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.