If that were so, then why would the Soviets have bothered to plant and recruit atomic spies like the Rosenbergs? That was a lot of trouble to go to, just to get ahold of secrets that were already on their way to Moscow. According to you, the "wildfire" would bring them all this information just as fast as espionage would. Are you suggesting the Russians were too stupid to know this?
Now that I'm starting to do serious research - against my will - my opinions are changing. It now seems to me that the Soviets thought they could save serious time and money through espionage.
But I'm only a couple of hours into it. I don't take my present opinions any more seriously than I took my earlier, completely casual ones. I'd argue them but I wouldn't be surprised to find that these too are wrong.