Could it be that Welling hopes to still be a big-screen Supes one day, say, maybe in this Justice League movie that won't have Bale, and, if GL2 is made right away, might not have Reynolds either? Does he figure that if a Justice League movie will have actors all to itself, i.e., Cavill won't be in it but will
be in additional stand-alone Supes movies, that he'll get a mega-movie-sized paycheck at last?
If that is
his thinking, then continuing to tease and bait fans by not suiting up in Smallville
would be the perfect way to keep buzz going.
... Or, maybe this is just wild-monkey speculation, and he's just a dick.