It makes sense that the driver package enabled overclocking should be a feature the manufacturer has control over. It's senseless and stupid to overclock a notebook GPU in the first place.
nVidia probably started getting calls from one of the OEMs like Dell or HP showing that many expensive warranty replacements were tracked down to GPU thermal issues. At that point they end up in a bad situation with the OEM because the customer has long gone with the replacement hardware and it is difficult to pin the blame on them when they are going to plead ignorance. An overheating GPU probably means a complete replacement of the motherboard and CPU, possibly even RAM and SSD on boards where all of that is integrated and soldered direct to a single system board. In some situations it could be melting plastic housings and causing battery failure. That's a lot of wasted product because some idiot wanted to run Minecraft a few FPS higher.
"Things you can't have because others are too stupid for $400, Alex"