It's OK jumping on the 'lets knock continentals' bandwagon.
Ok, some of them don't tick all the boxes, but many do.
Neighbour of mine has AA, and certainly has more cows running around with no calf/ stunted calf than you'd expect , so just plumping for "native" or "maternal" ain't all you might think.
More variation within a breed, than between breeds.
Was looking at Genus catalogue this morning having a brew, you'd be surprised how easy calving some of the BB bulls are.
(Hard calving bulls are also available)
There wouldn't be such a huge continental influence if they were all cr*p, and natives had sunshine coming out of their rs.
Didn't see this thread as being native v commercial thing myself.
More about the extreme beef heifers being kept for breeding more of the same and @johnspeehs opening observation of how the guys working that system manage to get the numbers to stack up.
Agree there are types of most breeds that will give you a cost efficient sucker cow. I think @AF Salers hit the nail on the head with the female shot putter comparison. Plenty of those go through the store ring and get bought by other suckler men for breeding up here.