Dated recipes are getting removed in 1.22 I believe. So after that it's only a matter of time until all the dated gears get either materia'd or vendored.

I'm sure there will be some people who keep some items though, like for example the pink coatees (since you can't make pink anymore). In 2.0 though you'll be able to dye gears pretty much any color you can think of, so by then there won't really be a need for it anymore.