IMO Mom Jeans were not slouchy on top and also were not quite as tapered as today's super-stretch jeans. From what I remember, Mom Jeans combined a high rise, worn high on the waist with the crotch point in place, with possible pleats poofing out in the front, a tight butt with another too-high rise, and a tapered but not skinny leg. For instance, I can't imagine tucking MJs into tall boots. MJs also had no drape - if there was slouch, it was unintentional from ill fit or bagging out.
To my eye, today's slouchy pants are meant to sit on the hip with the crotch dropped, and the legs taper more dramatically to more of a skinny-leg fit (some start near the knee, some just down at the ankle), drape/slouch in the legs/hips, and intentional butt/thigh surrender.
Eh, now reading that back it sounds complicated... did any of that make sense, lol?
