The reason why I think that the explanations people have given for their own lack of participation are largely irrelevant is because they mostly come down to this: we didn't have the time or interest. And I don't see that changing. The time issue, especially, is a matter of outside factors, and that's something we can never control -- therefore, not useful to the discussion, except to the extent that it applies to the January book.
Teresa, the time issue is entirely relevant to the discussion. People have to weigh the time they have against the time allowed and the time allowed was chosen arbitrarily.
The time people have, as you say, is largely a matter of outside factors but the time allowed isn't.