OEMs don't care about parts being unlocked or not, they care about TDP. Just look at machines like Dell Precision 5820, a professional workstation, using unlocked chips.Who are we kidding ? No OEM will use the unlocked parts and interestingly enough the 9400F survived just fine without the iGPU and media components.
The integrated GPU is there because OEMs demand it for certain products, and for now Intel doesn't make separate dies for the retail market. Probably >99% of all K-SKUs sold never use the integrated graphics anyway, so it's a waste of good silicon. I expect when they move to a more MCM design they will drop the integrated graphics in K-SKUs.