look at it this way, if an airline advertised a return fare from SYD to LAX for $1142(per adult). Kids are very roughly 75%, so 2a + 2c = $3997. Bet they would get many more takers if they advertised $999 (for everyone) + the power of price points is enormous. Having worked in retail for 25 years, I can tell you, $999 is about $200 or more, less than $1000, in the mind.
Maybe a good way to move seats, is to say ...
1 seat (booked at same time, same itinerary) $999
2, $979 each
3, $959 each
4, $939 each
5, $919 each
6, $899 each
or instead of dropping price, give something away, like extra ff pts, increasing for each person the more in booking.
or offer the 10th seat free. It's amazing how one person, can get 9 others to go, if he/she is getting a free ticket.
So first you advocated a price rise for group bookings for increased revenue, now you want a price reduction for all? Opposite approaches. They're already reducing price on some routes to try to get bookers. But if you reduce everyone's price including individuals it means a more significant loss of revenue, rather than only giving a group discount as the child's price does.
Sure, that could equally be spread to groups in general - but sometimes there are groups of individuals where overall cost is less of a concern since everyone's paying for themselves, which is different from one family getting lumbered with the entire cost. So again, a greater hit to revenue and less specifically targeted including more who aren't so price impacted so price sensitive.