The problem with your analysis is that numbers are much more comforting than less tangible things like superior training and defensive emplacements. Congress would have struggled a great deal with the desire to acheive numerical parity in every detail.
Another major problem with the numbers game was the pull out of the French. Without nuclear weapons - that is, without having the ability to independently deter aggression - would France necessarily have effectively pulled out of NATO? I think it might have been less likely. If French divisions had been added to the NATO OrBat in Germany, the numerical situation would have been somewhat alleviated, especially when additional US forces would have been added.
Could Great Britain have provided more ground forces? Personally, I doubt they could have done much more, although perhaps the BAOR could have been somewhat strengthened. The same can be said for Belgium, the Netherlands, and Denmark. I can't really see Italy providing major ground forces in Germany, or, for that matter, any of the "southern flank" NATO nations (if they existed at all, which depends on the year in question).
The biggest opportunity for military expansion, I'll say again, would have been Germany. Had NATO not had nuclear protection from the United States, and if the only counter to the conventional forces of the Warsaw Pact were conventional forces of their own, then I really can't see NATO nations opposing a bit more German military power. Naturally, Germany wouldn't have built a 2 million man army, or anything of the sort, but a modest increase wouldn't have been out of the question, IMHO.
Remember also that until 1972 most US troops were conscripts too, and in the 1960s troop quality suffered a great deal.
Furthermore, after the well know debacel of the Maginot line the NATO powers would not have been satisfied with a static defensive policy
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