As a retired singer, I can see both points of view here, I used to do a parody of 'When I first came to this land' which started:-

When I first began to sing, the audience couldn't hear a thing,
For all the talking at the back, so I did what I could,
And I sang up loud above the crowd,
For the songs are sweet and good, so I did what I could.

You then add layers of amplification at each verse until:-

But now when I begin to sing, The audience still can't hear a thing
The reason it's not changed today,
There's a bugger over there with his own PA........

However, I currently get my musical fix from a local Jazz Club, and I have frequently said that, given the level of actual listening to the music by the audience, I could have carried that room with very little in the way of amps. Ian Shaw, the pianist proved the point last year when he told the sound girl to switch everything off when he closed his set with 'If Love were All' and you could hear every word.
I think the key really is are the audience there for the music or the beer!

BrianQ