As far as I would go with high speed data over power would be just locally inside the dwelling. Using distribution lines seems like sheer foolishness to me.
The only way that power distribution lines should be used is to replace the core of the power line with fiber optic cable. But even that seems cost ineffective when you consider that the power company owns the right-of-way and can run fiber cables on the poles below the power lines.
Actually, the City/County/state owns the right of way, and leases the space to the utilities in the form of "Franchise fees".
As far as running fiber above ground, there is a minimum distance between each utility, or voltage on a pole. When I worked with CATV systems, the phone lines had to me below the 240 volt lines, and our lines had to be three feet below them, yet maintain a minimum distance above ground. Around 10% of the poles had to be replaced, at our expense, because they were too short to add another utility.
Of course, the electric company that owned the poles knew a CATV system was to be installed, and stopped replacing old poles unless they broke, so whoever got the franchise would have to pay for new poles, plus the monthly "Pole attachment fee" AKA "Pole rent" to use poles we paid for.
Both the telephone and CATV companies have an advantage in the fact they can just lash the fiber bundle to their existing cables without adding new strand, and needing extra pole space.