First, there’s a thread from 2024 Sound mixing at concerts and shows SUCKS that discusses this. The second part is that often the “check 1 2 3” business is for setting levels on the stage monitors, not the loudspeakers that the audience is listening to. I just attended a show by the Soweto Gospel Choir, 17 singers, a keyboardist and a percussionist, which is a pretty challenging setup since about 8 of the singers kept taking turns as lead. I noticed that they were handing off microphones while taking lead, then going back to mics set on stands once done. Overall, the sound mix was pretty good, but this was also at Koerner Hall in Toronto, which is part of the Royal Conservatory of Music, one of the premier music schools in Canada, so I expect the sound board engineers know their stuff.