The ultimate test of your proposition never happened.

Had the Red Army tried the Fulda gap with its thousands of t-72s and t-80s against the newly deployed Abrams, Chal-1 and Leopards, then we'd have seen the answer -- at least until the tac nukes were brought in.

For offensive operations, numbers help. Blitzkreig requires strategic shock and a larger number of mobile tanks can create that more quickly. If they are weak tanks, however, combat with reserve formations will NOT go as planned, so they do have to be comparable.

On the defensive, number are somewhat less important. Devastating firepower is key, as is the armoring to shrug off artillery barrages and the like in the opening stages of an assault.

What a far ranging and interesting discussion.

Seamus