"One terrible example is watching Woody Guthrie and Pete Seeger... "
Both Woodie and Pete were 'performers' rather than 'fireside singers, and as such they were, in my opinion, very effective in what they did
Their imitators made the mistake of not distinguishing between the two
Our oral traditions evolved via domestic situations where the singers and storytellers did their thing to family and friends amid intimate and familiar surroundings
Having said that, if you manage to familiariarise yourself with your own voice and learn to use it you can handle the whole range, from tender lyrical pieces to shanties and work songs

The Critics Group used exercises to do this - starting from ones to find the natural voice based on four vowel-type sounds, then singing exercises to learn to handle different aspects of tunes
1. Rocky Road to Dublin; a verse and refrain sung in one breath at speed for breath control and accuracy of articulation; mouth music - Tail Toddle double chorus and verse sung in one breath covers more-or-less the same territory
2. Gilbert and Sullivan 'First we polish off some batches" (from the Gondoliers) for accuracy of pronunciation at speed
3. 2 pieces from Wagner's Ring - "Tis Ended" for handling large intervals and 'By Evil Craft" to sing minute intervals - down to quarter-tones
Coupled with relaxation exercise to make you aware of and control tension, this covered the technical work that we, as singers, needed to understand your voice, put it into shape and keep it there
It takes a short time to learn them and, once learned, they stay with you forever - as I am still finding half a century later
The only problem with them is remembering they are exercises and not objects in themselves
Jim