This is actually less drastic and more complex than the press is making it sound. FDIC is funded by the assessments, if the draw on it exceeds the inputs, it obviously needs more inputs, which has to be announced at some point whether that is going to make the unicorn poop Skittles faster or not.
Yet on top of that, the $250K level also drops back to $100K in coverage in the near future (unless Congress extends it) so just given the same rate of demands for payouts, the maximum liability per claim is about to drop by 60%; hard to say how that is costed in, but I would expect FDIC's projections involve a worst-case (in a purely-technical sense, and strictly from an insurer's point of view) of the maximum limit remaining at $250K.