Is there something inherently and mathematically "poor" about the .277" diameter that does not lend itself to high B/C bullets, or has there never been interest in making anything other than standard B/C bullets in that diameter?
That is to say: Has the .270 Win (or WSM or WBY or whatever) never been asked to perform at long range?
It was designed for the shorter bullets of its time.
The bullets and twist.
With the Weatherby being the only other option in that caliber,
It was twisted the same.
So, no one wanted to make bullets that wouldn't work in the barrels available.
In turn no one made barrels for bullets that didn't exist.
25 caliber has the exact same quandry.
