I don't know about the USA but, down here, I couldn't get access to the ducts or permission to dig up roads etc. to lay fibre. (This is me pretending I could fund it at all). The existing phone companies have a statutory right to do things like this and they jealously guard their exclusivity. I know a similar situation prevails in the UK.
On your second point, I don't know anybody who need GB bandwidth but, in this day and age, most people need better than the 4 Mbps I currently get. Note that I'm talking bits, not bytes. More and more of our daily life now happens via the internet--conventional delivery mechanisms for TV and phone are shutting down with a web connection the way it's going to be. On top of that, as I mentioned before, our household of 3 people has six internet connections sharing that 4Mbps.
The plan in Australia is called "The National Broadband Network" and, as originally conceived, was going to provide a fibre, satellite or fixed wireless connection to every user in the country. Part of the reason this made sense is that due to all sorts of historic issues with the monopoly telephone company, they ceased doing any maintenance or upgrades to their copper structure, causing big problems now that we try to do more than just make phone calls (and even problems with phone calls sometimes!). As premises are connected to the NBN, ordinary access is to be ceased--even if you only use a phone and no internet you'd still have a fibre connection and do your phone calls via VoiP (with a box making this transparent to the user).
Our current government has muddied the issue greatly by deciding to try to use FTTN rather than FTTP. This means fibre to a local node and the use of existing copper for the actual home connection. FTTN has been tried in the UK and New Zealand and both countries are phasing it out to use FTTP instead. I'm lucky in that I'm likely going to be one of the last neighbourhoods to get FTTP since we were planned before our current political idiots started doing Rupert Murdoch's bidding (Murdoch being the owner of the monopoly cable TV provider in Australia).
On final point is that, while we argue about whether 2 or 4 or 8 Mbps is enough, places like Hong Kong and South Korea already have connection in the hundreds of Mbps and are even now planning upgrades. Unless Australia and the USA and the UK can match this, it will be US who are the"third world" a few decades from now as more and more of our lives move to online.
