One maybe USSR would have created one 10 or 20 years later, while USA would have none... Hindsight is 20/20.
Why do you think no other country could match USA R&D now or in foreseeable future?
Why do you think no other country could match USA R&D now or in foreseeable future?
And if that had happened, US (and rest of world) would've been really screwed. Manhattan Project used 1/7 of all electricity generated in US at the time. No way such gigantic project could've been conceived and completed in peace time in US. And definitely not fast enough if USSR had developed it first.