Much of the equipment in FFXIV follows a pattern where every 10 ranks there's a better version made from more advanced materials, for example, the R24 Canvas Doublet Vest is replaced by the R34 Velveteen Doublet Vest, and the recipes are very similar apart from higher-grade materials. It seems like many of these patterns, with the exception of the Coatee outfit, stop in the 30s. However, there are higher base materials available.
As a concrete example, let's go back to the doublet vest. The highest one available is the R34 Velveteen version. It's made from velveteen and buffalo leather. But these are not the highest-rank cloths and leathers. We have linen and wool. We have toad and boar leathers. We even have mythril buckles. So why isn't there an R44 doublet vest made from some of these materials?
This phenomenon is not limited to doublet vests, where is a pair of R41 Electrum Spectacles? What about an R46 Linen or Woolen Robe or Hat? How about even an R36 Velveteen Doublet (not vest)? Or the half-robes, which don't even have a velveteen version? Some of this gear seems to have models for it: there are NPCs wearing what appear to be Seafoam-Blue Linen Robes (Ul'dah Adv. Guild) and Dark Violet Woolen Half-robes (CON Guild). Why can't we make it and use it? With the new direction equipment is going, will we ever see it? If so, when?
tl;dr: We're clearly missing some gear recipes for the R40s...