No one claimed 60 million licenses mean 60 million users. But when this figure is comparable to the Win7 figures you DO have a very good indication of how well it's selling, because the Win7 figures had all the same variables.
What I am saying is that the figures claimed by MS don't tell you much that's useful.
MS shipping stuff doesn't tell you if the product is selling or if it's sitting in OEM warehouses listening to crickets.
60M licenses sold and minimal stock at OEMs would be a good result.
60M licenses sold and most still in stock at OEMs... not so good.
You need to know the second half of the equation to get the full picture, and OEMs are claiming it's not happening.