There must be an option of CC/ 3A available, and also, I believe not all opt for them. It all depends upon the fare.
I really don't compare intercity travel with Memu travel. The "class" and "purpose" of people travelling are extremely different.
2S or second seating is the most widely accepted coach for ICE travel. If they introduce VM with a fare slightly higher than 2S, I do expect people to shift, given they get a "reserved" seat.