Haven't read the article, but "revenues" would suggest cash flow rather than profits.  In other words, if your logic is correct (and I am inclined to think it is), this means that 51% of profits preceded the current milestone. 
 
 
The problem is that the articles are rather vague and even included fundamental errors. 
 
 
 
This graph in the NYT says that downloads surpassed CD in terms of units sold, but in terms of value, downloads represent much less than CDs 
 
I think the simple reason for this is that for downloads the unit is one track, as tracks can be bought individually. So it's no surprise that the number of usits is high, but that the value is much lower. They should divide the download units by 10 (average number of tracks on a CD) in order to compare both formats. 
 
 
The other thing is, what are they counting, geographically? Physical unit counts will be sales in the US. Downloads could be from anywhere in the world. 
 
MG