FQ,
the advantages of the bolt gun are weight, simplicity, size and accuracy.
disadvantages are rest: capacity, reload speed, shooting speed.
But, yes, you're right, the most basic question is 'Is the Scout Concept valid today?'. Or was it ever?
I've never picked my One Rifle. I've not shot any rifle enough to form an opinion as to reliability, weight and accuracy. Heck, it might be a shotgun. Would the One Rifle be the same as my Go To Gun, my TEOWAEKI Gun or my Bug Out Gun? As an urbanite, if forced to evacuate, keeping the rifle concealed is of utmost importance. I might choose a folding stock AK as it fits in a backpack or messenger bag. If I were to Bug Out into the mountains, I might choose a M1A, although I am partial to pistol grips. For the end of the world, I'd choose an AR15 as I'd expect it to be easier to find parts than anything else.
I'd choose a 1911 for my One Pistol, assuming I didn't have to conceal it. It fits my hand well and I can shoot it well (OK, I suck as an USPSA shooter, but I'm still happy with my performance)