oomis – Not to be motzi la’az, but you can’t put Helfgot in the same sentence. As Yossele. (See what I did there?) At best, he is a chazunishe singer.
Also, I wouldn’t say that Kossevitsky reached his notes effortlessly. Watch videos of him singing and you’ll see that his face turns beet red. In contrast, Yossele barely moved when he sang.