Most likely, it's just a matter of time and the NVIDIA DGX Spark is partly serving as a pipe cleaner product. They clearly need to work on power management, and solid Windows support may be more work than the Linux support they've shipped so far.

Mediatek-based laptops (other than the existing Chromebooks using what's more or less Mediatek phone chips) are one of the big things to keep an eye out for at CES next week. They have a solid market opportunity to provide an alternative ARM solution to compete against Qualcomm's Snapdragon X Elite and upcoming X2 Elite: having a NVIDIA GPU would give Mediatek a huge advantage over one of Qualcomm's most pronounced weaknesses, and the CPU cores Mediatek is using are probably "good enough" for a GPU-focused system (mobile AI workstation or low-power gaming laptop).