I agree the .50 alaskan will penetrate better but when I object about shotgun ballistics, it is also mainly because the speed is too slow.
Hunting conditions in Europe are fairly different then in the US where in fact I started to hunt. In the US the standard is still hunting or from a stand and is rarely on running games chased by dogs.
In europe, still hunting is usually done with flat trajectory and accuracy in mind; This implies medium caliber and high speed (not ultra high which leads to bullet fragmention), the standard being 7mm Mag; 300 Win, 8X68, 7X64 and its followers the .280Rem and .270 Win although the best are the magmum because big boar are tough.
When it comes to drive hunting which is uncommon in the US and even seen as unethical (it was also my opinion initialy but I changed), things are rather different. Animals are full of stamina, run fast and react differently, shot placement is not always optimal even if you shoot at short range (which should be, as long shot are unethical). Surveys have been made and showed that in these conditions, big heavy bullet of medium speed are the best choice, like the 9.3X62, 9.3X64 and 9.3X74 for double rifle (35Whelen, 444M are in the same league). Medium speed (~700m/s) because a high speed would be a waste not to mention the recoil and a low speed means to give more lead like when wing shooting with a shotgun. Note the brits discovered that at the turn of the century in africa so nothing new.
Blaser started to produce for their linear bolt rifle the 45 Blaser (a kind of rimless 45X70 ) but it failed to achieve any success because they are simply too slow.
A new caliber the 9.3X66 has just been, released, this one could meet a better fate, right bullet but a tad faster. without excess.
I personaly use the Win 94 444M for drive and although it is the lower limit for speed I like the lever for its handyness, quick follow up, safety and look.
As said, there is no one size fits all in the gun and ammo business. Not even combination guns where you have one small caliber for pest, one medium for big game and one smoothbore for birds.