If this were cost-effective, why wouldn't they just buy DGX Sparks, with similar performance at similar price points and a more convenient form factor?

Or RTX Spark and run their workloads under WSL, which as the article notes, has minimal overhead relative to running Linux directly?

This sounds more like a bug than a feature, especially given that Linux on battery runs at full clock speed and downclocks when plugged in, and Windows does the opposite, suggesting they could at least mitigate the problem with no changes to their software stack by inverting a conditional in the firmware and adding a Linux kernel parameter to control memory allocation as apparently already exists for Windows.