The fact is that alignment based yoga is a very new addition to yoga generated largely by Iyengar and his troops. I have a self full of 'older' yoga books, all published before 1965 and not one of them references alignment in any way. Clearly, the first wave of yoga to come West did not focus on alignment but on the simplicity of the asanas combined with a meditative presence.
Yoga teacher and blogger, J. Brown has recently written about alignment regarding it with suspicion saying that safety in yoga has little or nothing to do with alignment. Here's an imaginary conversation he had with an alignment based yoga teacher:
Teacher: “I believe in proper alignment.”
Brown: “OK, well, what do you mean by ‘proper alignment’?”
Teacher: “You know….neutral pelvis…shoulders sliding down the back……”
Brown: “Yes, I am familiar with those cues. But this idea of alignment, where does it come from?”
Teacher: "I think it’s scientific.”
Brown: “Respectfully, I question that. I think these are arbitrary ideas that are not based in science so much as the dictates of charismatic men.”
The bottom line for a solid, satisfying yoga practice: Let your body guide you to the best positioning, move slowly and do it with a gentle meditative mind.
Read more of J Brown here: https://www.jbrownyoga.com/blog/2018/6/proper-alignment-in-yoga