Fiber optic service doesn't necessarily mean fast...it's just an efficient way for the Telco and now the ISP to get data to your house.
Ma Bell started running fiber optics from the Central Office a couple of years before Al Gore invented the internet. My subdivision(built in the late '80s/early '90s) has a big box up in the front that South Central Bell(later Bell South when they merged with Southern Bell, and now AT&T after they merged back with AT&T a few years ago) installed when the place was built. They ran fiber optics from the central office downtown to this box, and have copper running from it to the houses in the neighborhood. Running copper that far gets really expensive really fast, and after about 15-20 miles from the CO call quality starts to deteriorate pretty dramatically.
When the local cable company decided to get into internet about 15 years ago, they redid everything out our way to fiber optic. They then got into the Telco game with VOIP. So, now we have one box running to our house with fiber optic coming in. It splits off to coax(for both TV and internet) and two-wire copper for telephone service. The box also has to replicate all the elements of a traditional telephone line(+24V for talk, 350Hz and 400mHz simultaneously for the dial tone, and 100V at 20Hz for ringing). The internet speed is governed by local load, and will never exceed what we've paid for them to provide.