Why is there more MK-4 and MK-7?

"MK-4 form of Vitamin K2 is the most abundant form of K2 in the body and ideally the diet. The MK-4 form of Vit K2 comprises about 40% of all K2 in the body. And the remainder comprise mainly MK-9, MK-8, and MK-7, in that order. So, you could say MK-7 is the fourth most important Vitamin K2. MK-8 and MK-9 are not stable in supplement form - as of this writing. But they're found in hard European cheeses. Yet, both foods and supplements rich in MK-4 are uncommon. If you shopped for Vitamin K2 supplements, you'd think all we needed was MK-7. Not so. It's a fair estimation that we consumed (ancestral, pre-industrial diets) between 500 and 100 mcg of Vitamin K2 as MK-4 daily and that is what this formula provides. This formula (500 mcg of MK-4 and 100 mcg of MK-7) is based on an estimation of ideal/ancestral human diet, back when we ate a lot more organ meats, fermented foods, and the animals we consumed ate grass."