[pinewurst]

That would be workable only if missions entailed takeoff, climb to 30,000 feet, dropping bombs and returning.

Much of the design difference between an airliner and a strategic bomber is due to extreme stresses from flying balls-out speed at treetop altitude. Older B-52 variants (pre-G) were retired when they couldn't take the load, because they were designed for max altitude cruise and weapons delivery. A big part of the B-1A to B-1B redesign involved removing the fancy high-altitude air intakes and restressing for extended treetop flight (and reducing RCS).