Well the reason I came to the conclusion is because I tried to brute farm the rest of my enigma once I had the first half (cubing up to the ber) yet the rune or rune alternative options never dropped. And at a certain point you start creating problems trying to farm things that are unreliable in terms of farming potential. Problems related to health like carpal tunnel start to be a strong possibility with repetitive motions on farming that requires hundreds even thousands of hours.
Regardless of the piece of rune, the medical condition exists, so that point is a bit null.
As for farming the rest of you enigma, not really sure the issue. SP has LK runs while online has trading which it is quite easy to farm up a bit to exchange for a rune. I get that not everyone has all day, but it is quite doable very quickly to trade up to a full well built character.