previously, you could browse and read T2W without joining.
then, the system was changed so that you had to register in order to even read posts, let alone post.
so, you could argue, once registered, newer members decided it wasnt for them.
(I wont go into conspiracy theories about it being a means of bumping up the membership numbers for advertising purposes)
The number of posts has no bearing on quality of traders. It could simply be T2W is not appropriate for most members, and they never return. Lack of posting is not connected to their ability to trade or otherwise.
There have been similar threads about the proportion of the membership that have "last visited" T2W (in last 6 months, last 3 months, lat month, etc). Thats more instructive, as someone returning to read (without posting) finds value at T2W.
As per rav700, T2W is more a distraction to help avoid over-trading.
Have a great week. Glad I'm inside from the rain.