Oh, but Lenny.
I've done every deer (but one shot with a .308 at about 20-25 yards) & antelope with a .243 well past 300+ yards.
Shot placement makes all the difference.
Don't want to turn this into anything "says you"-wise, but there's plenty cartridges that'll do stuff way out there.
As a counter, we could argue, just as well, as to what's the best "brush buster."
The .300 mag's a wonder, no question, but still, for much of most our practical limitations, a .308, or .30-6 would do just as well.
... & so would a .280, .270, likely a decent enough load in7-08 & quite afew others.
Onlyest thing I could say is the hunter makes the kill, the rifle (or bow, slingshot, or ?) is only a tool used properly to do that.
Having caught a couple desert quail by hand, I can easily enough say, nobody "needs" a shotgun ....
A .300? Absolutely! Go in peace & make sure you use a properly expanding bullet, sight it in & be sure of what you do.
Everything else is hunting ethics.