I know you love Elvis, as do I, and I know you are coming from a good place in defending him. All power to you for that. I don't think those changes would have been an attack on Elvis though or in the least bit mean-spirited. Maybe that's because I don't think it really matters that 1 billion didn't tune in for the broadcast. More important to Elvis' legacy is that the facts of his career are correctly presented and preserved. And the most significant facts about Aloha are that it was an innovative and groundbreaking project that was pulled off in 1973 and is still popular among fans nearly 40 years on.
To be clear, the 1-1.5 billion figure that was originally predicted by Colonel Parker (and subsequently often spoken of as the live broadcast audience) was derived by adding together the populations of all countries that carried the broadcast in 1973, including the delayed broadcasts in Europe and the US. That would actually get us to about 1.3 billion if every single person - man, woman and child - had tuned in. Clearly that's impossible, eg in the US, approximately one-third of tv sets were tuned in. We'll never know the exact viewing figure for all broadcasts in 1973, let alone the live broadcast figure, but 1 billion or more isn't feasible. Several hundred million was still impressive though, particularly for 1973 when the world's population was half what it is now.