Request #18272 has been accepted by diabonas [1]: Merged r-gdal into r-rgdal, see https://lists.archlinux.org/pipermail/aur- requests/2020-March/038366.html The maintainer of r-gdal has been made a co-maintainer of r-rgdal as well.
[1] https://aur.archlinux.org/account/diabonas/
