I always treat those "end date" comments as something of a moving target. Especially as he himself notes that "the tale expands in the telling" often times.
I think simply noting that the comic has an end date and won't continue forever is sufficent.
ETA: Although also noting that he might revist the World of OotS after the main comic is over might be of interest (that was in the podcast, but I don't know if it's been transcribed or not yet). But, then again, "might" really doesn't say all that much, I suppose.