If a dedicated core group of WW1 enthusiasts scheduled some events, they might be able to draw some folks into it. Problem is, nobody goes into the WW1 arena because nobody is in the WW1 arena because nobody goes into the WW1 arena.
If that alone was the reason, we would still have a lot of players in WW1, because once we had tremendous numbers there. The numbers did not fall because nobody was there in the first place. But of course I agree in as so much as once a certain threshold is crossed, the "nobody goes there because nobody is there" adds up significantly to the problem.
And we do have a core group of enthusiasts, and they actually did schedule some fights and events, with some good turnout if my crappy memory and my stats don't fail totally.

But similar to the AvA, any such effect is only lasting for a short time. A few players more will show up, have some fun, but then again they get drawn back into the LW for the very same reasons as before.