I'm not really sure what to make of your first paragraph...
As for your second paragraph, I know somebody that does get first round hits at a mile occasionally. First round hits really aren't always a priority at that distance. Many times they have time for follow up shots. In that case, I do know someone that will get a solid hit within his first 3 shots. In fact, he just did a video with Litz at Berger ballistics on long range shooting.Anyways, if it was an important shot, I would send 3 rounds downrange, before the bullet even gets there. Either way, that's all not really relevant. Most of us here shoot for fun, at nothing more than paper or steel, and aren't in 'sniper' situations.
As far as the 300 win mag vs 338lm at 1500 yards... I want to see something factual that shows the 300 win mag performs better at that range.
Theres a reason why almost all people that shoot a mile+ use some form of 338 (lapua magnum, norma magnum, edge etc...).