When/How will postal mail go away?

Businesses like The Gas Company, The Water Company, The Plumbing Supply outfit still send paper invoices and statements to most of their customers. These businesses spend millions of dollars each year in postage alone (not counting paper, printing, labor, etc.). In this country alone, one million men are walking up to mailboxes, hand-picking-up, driving, sorting, re-sorting, driving, and hand-delivering stuff - at an enormous cost and waste (both in terms of dollars and in terms of the environment). In this modern day and age, it’s absurd. We’ve got e-mail, IM, twitter, etc. The question is, when and how is this finally going to change? Zumbox launched yesterday - "the alternative postal service". Is this the answer? Thoughts? Here's the Zumbox environmental case: http://www.scribd.com/doc/9405157/Zumbox-White-Paper-Whats-the-real-cost-of-42-cent-stamp