I agree with opinion that PSK should be assembled not based on what may get useful, but what will be essential in a real emergency when you do not have access to your backpack, car or other. The situation, when some items of equipment will improve your chances to survive, I mean, not to die. All the rest can be put into the backpack, including food and water. If you use snares, slingshots and fishing equipment when you are not in danger, you can put them in a backpack as well. I agree with opinion that, the bulkier and heavier the PSK will be, the less desirable it will be on you all the time (not backpack), hence, you have less chance to have it on in a real emergency situation. If you store PSK in a backpack, you should treat your backpack as your PSK (and I agree, backpack also PSK to some extend, but large one, however, I believe most people want to have it easy to carry). To my opinion, PSK should be used as the last resort when everything else had been tried to escape danger. To my opinion, GPS and Communication equipment (Satellite or mobile phone) is the best PSK for most real emergencies, therefore should be on you all the time.
I would also agree that there is a little chance that you may get into a real emergency under equipped, if you expect it.