All due respect.. your ascertainment is made from a flawed perspective in two ways;
1) You cannot compare amateur students to professional fighters (assuming that's what you meant) in any venue, even the same one, other than in terms of tactics and principles learned/utilized within said venue.
2) Kuoshu rule structures have never allowed any sort of continued ground fighting. The closest the rule set came was way back in my day when we were allowed to strike once as a finishing move as the opponent hit the ground.
To have first hand knowledge of what we do on the ground, I guess you'd have to come visit. As I am certainly now too old to compete any more.
Also, both you and HW108 seem to be ignoring something else I said. So I'll restate it here: Although we CAN go to the ground and stay, it is not our way. Our way is to punish and get back up. This is something that has been stated by others as well.
Seems to me that there is a bit of confusion (or maybe it's just me) over the terms "ground grappling" and "ground fighting". TCMA can do the latter. It is not our way to engage in the former.
A "submission" in current sport framework translates usually to a damaged/broken limb or neck in old style framework.
Our way is to stay mobile and not engage longer than necessary on the ground.
But hey, I'm not here to convince anyone. In person is better.