The Russians had some really big intercontinental bombers at the time ~ we didn't.
What are you smoking? Show me a link to a WWII Soviet bomber that matched the B-29, or the 17 for that matter.
http://www.fas.org/nuke/guide/russia/bomber/tu-4.htm ~ we are not talking about the most technologically sophisticated planes here, but check out the quantities ~ 12,000!