I've seen that ARCore has a few compatible devices (Samsung or Google Pixel), which also appear, along with a few more Android and Apple devices, in the compatible devices of ground plane detection in Vuforia SDK.
Why only those devices can support this technology and others not?
A CPU power problem? Possible
Marketing? Probably
Both? Surely
All ARCore-compatible devices are also compatible with Daydreams (or Tango) and ARM processor. These are certainly powerful devices but other smartphones that have nothing to envy in terms of power are not compatible. I think that power plays, but not only for that reason.