Gigabit FTTH is not technically difficult; it's just expensive to install. Google is supposed to be working on some secret sauce to make it cheaper, but they haven't revealed anything yet.
How is Gigabit FTTH different from ordinary FTTH ? Is it the fiber itself or the equipment on the endpoints ?
I guess these days FTTH is all Gigabit, but I remember a few years back when some companies were talking about 100 Mbps FTTH; that's nearly pointless now that cable can deliver that speed.