Firstly, I too saw Journey Last summer at the Sleep Train Amphitheatre (Sacramento) and Augie sounded fine. Castronovo was not singing that night either, so aside from Jon and Neal each singing a couple songs, and Ross 1, SA carried that show.
Secondly, I have seen Journey with SP and SA. In his prime no one could touch SP voice, I think we all agree on that here. I also think most of us here can agree that Perry's voice is not the same as it was in 1986 even. Not saying he can't sing, just not the same. Now, as far as Perry's physical performance is concerned, I really don't think Perry at 60 (or close to it) is going to be running around the stage and entertaining people the same way he did 20yrs ago. Especially after Hip surgery
So you can not, IMO, compare SP to SA now, using SP from 10 to 20yrs ago as a reference. The whole band is older, and therefore there presentation (live performance) is tamer yes, but IMO more straight forward.