Well, Les Paul I guess for one - used Fender Twins live on stage - but in the studio it was clean, perhaps even ultra-clean as his goal. Tubes in the recording kit of course, but he spent a long time trying to get a pure sign.
John MacLaughlin was often seen sans-amp, with a Mac doing the processing, and amongst the very able church guys, it's very popular. Volume might be king for some kinds of music, but it's incredibly genre specific. Pit musicians, jazz, ambient and world music rarely needs volume on stage - volume for the audience is done by the PA. Pod and processor users are one type of player, somebody else is more than happy plugging a guitar into a Marshall with 4x12". One rule does not fit everyone, and saying it does just proves blinkers are being worn. Eddie Van Halen isn't going to play quietly, but plenty of people do.
Shows what happens when you post and don't expect people to disagree, doesn't it?