"When my wife and I worked as a duo and later as a quartet" - cloning!

One thing that amplification does it make it possible to bring together impossible combinations of instruments - a brass-section together with a mountain-dulcimer, for example. Whether that is a good idea I'm not so sure.

In a big room or with a noisy crowd or on stage amplification is necessary of course - but when you get singers who get too used to murmuring into mikes to the extent that they can't cope with singing without one in a small room , you've really lost something. The heart of folk music is the unamplified music. And the heart of singing is the unaccompanied song. And when the heart is sound, you can add on all the other stuff.