The site speculates this is unlikely to change in the near-future:
Some of the OEMs we talked to simply admitted that despite the fact that Ryzen mobile is quite a good solution, the designs were simply locked years ago with Intel. In most cases, OEMs could not spare the engineers on a dicey project with uncertain success.
AMD has image issues to address in notebook space. And sitting in the lowest end designs and going from that to a premium flagship design is a hard process. Things might get better, but we question AMD’s possibility to surprise us with a follow up with a new mobile chip in 2019.