It won't do you much good at the North pole, for example, but in many other situations, it may give you a good shot for short term survival.
A 72hr BOB for the North Pole is possible weighing in less than 25lbs but it is going to get expensive, with your tent, sleeping bag, mat and stove etc.
http://www.phdesigns.co.uk/hispar-1200-down-sleeping-bag-k-serieshttp://www.phdesigns.co.uk/hispar-down-suit-k-serieshttp://www.terra-nova.co.uk/tents-and-spares/all-tents/voyager-ultra-2-tent/http://www.exped.com/en/product-category/mats/downmat-xp-9-lwhttp://www.primus.eu/omnilite-ti