Cam design limitations

I am trying to figure out how this works:

I'm told that I can't BUY a short duration, high-lift cam for my slant 6, from anywhere. I am talking about a 210-degrees at .050" lift profile (112 degrees lobe separation) with .530" lift.

The story I get is that to get that much LIFT, I have to have more duration.

That makes NO sense to me.

Why does it make no sense?

Because the implication is, that the lobe profile for the short duration cam is such that there's no material to grind, to get the desired specs.

B.S.

If there's a .530-lift cam that exists with say, 252-degrees of duration at .050" lift, the same blank could be used to create a shorter duration cam wth the SAME LIFT, the lobe profile just wouldn't be as "FAT" through the middle. It would just take some extra grinding... wouldn't it???

The material (on the blank) is THERE... obviously. This new, short-duration cam would have "skinnier" lobes...

What am I missing here???????

Can somebody explain why these cam grinders are so reluctant to grind the cam I want?

I'm stymied...