one of the biggest misconceptions about long range shooting is that you "need" bullet speed , this is nowhere near as important as a good bullet with a high BC , the calibers you mentioned do't see much use in the LR crowd because nobody or very few offer good LR style bullets.
For instance with the speed thing , a 308 can launch a 150gr basic hunting style bullet at 3000 fps , if that bullet is even going fast enough to make it to 1000yds without getting sideways it will be going so slow that the wind will eat you alive
But you can shoot a 190gr Berger VLD out of the same gun at 2500fps and the bullet will stay accurate out to probably 1200yds maybe more , so you getting 500fps less velocity but much higher BC bullet. The BC wins every time in LR.
another extreme example , I can get a 40gr bullet run out of my 22-250AI at over 4200fps , that bullet probably won't even make it to 1000yds.