Good question, and I'll share my thoughts.
The reason drum machines lack soul ( besides not having one to start with ) is because time/ and tempo are not exact sciences.
I find all this forum talk about metronomes and clicks interesting because while they are invaluable tools for practice and recordings, having a super- quantized drum track bang in the middle, dead center, almost always sounds sterile and souless. And while we aspire to fulfill our roles as good time-keepers to the music world, we need to aim a bit beyond just keeping good time.
You could be playing in time but sitting on top of the beat or be so behind it, it is a vast space that we inarticulatelly call 'feel'.
And that really comes from the drummer reacting to how he is feeling the music. Which is not easy for drum machines to do.
Music editing programs have quantization settings where you could swing the 8ths , 16ths, 32nds whatever to make the track sound more 'human'. It never quite does it , IMO.
I guess to be human is to be imperfect. And drum machines are perfect.
Thats a contradiction in terms.
Electronica,Trance, D n B , yes thats another world,, with its own rites & rituals.. using patterns of perfection to create imperfections