Mike, good to hear from you! You have an impressive background. I forgot to mention I am *mostly* a classical jujitsu guy too - and a karate guy - and a certified Modern Army Combatives Program instructor (still active duty). But I started with Judo, back in '79. Getting old brother. (Not boasting, just laying out the basis for my opinions.)
I think I was misunderstood. The single-leg IS scored. My apologies for garbling that up - although I DID put that in bold-face type!
You and I are both right about the single-leg name. I just found this link: http://www.nationmaster.com/encyclopedi ... g-takedown
"In Judo and other budo, there are many classifications of different types of single leg takedowns. Variants of the high crotch correspond to sukui-nage (掬投, "scoop throw"), where the opponent is lifted up from the ground, while the typical forward pushing single leg takedown is classified as morote-gari (双手刈, "both hands scoop") (similarly to certain double leg takedowns). Some techniqes are more specific, for instance kibisu-gaeshi (踵返, "heel trip reversal"), which is an ankle pick where the heel is grabbed, scooped up and the opponent is pushed and thrown immediately. In kuchiki-taoshi (朽木落, "one hand drop"), the opponent's leg is grabbed, pulled up, and used to push the opponent down to the ground in a split second."
I think the lack of ukemi with the feet is because of two things that are both related: it is not necessary because of the surface they are playing on, and they are ignorant of using their feet in that fashion. Due to lack of necessity, they don't learn it or train it, and are thus ignorant of it. That would be my guess.