While there is no reason you have to (they do get paid to make the call) on might have some sympathy for the gun company exec who has to decide WHICH of their products that do overlapping jobs gets the most support.
Knowing that pushing one will hurt or even kill off the other....
The only compromise possible is to allow the passage of time, to entrench one of them enough it will continue to have enough of a following to be commercially viable after the "new" thing comes out.
Look how long it took Remington to put out the .260. According to stories, it was intentionally delayed so as not to kill off the 7mm-08. I think it quite likely that had they come out together, or close together, the 7mm-08 would have failed. Remington had their big 7mm Mag (a resounding success) and also the 7mm Express (former .280 Rem) and I think the 260 (6.5mm) on the .308case would have beat out the 7mm-08 for most hunting. Those who felt 7mm was needed, had other (long action) choices.
So, the .400 beats the .350? imagine that!
Bigger bullets tend to work better, more often than not, and particularly when the velocities are similar or close.
Personally, I don't have an interest in either one, as I'm not restricted to them by game laws, and I'm not a fan of any AR pattern rifle for hunting, but that's just me...