Verizon upgraded to GPON in 2008, when prices were a lot higher. Back then, GPON line cards were in the $10-20k range. (And they're upgrading to NG-PON2 starting this year.) Also, their typical split is 1:16 or 1:32. So you're talking about $600+ per subscriber (maybe pushing a grand once you factor in cost new ONTs and cost of labor to install new ONTs). That's a couple of thousand dollars per subscriber over the amortization period (at least if you're hoping to keep up with the Joneses).