It's simple: the developer will build the houses as cheaply as possible and flog them for as much as possible. This often means the developer choosing the cheapest utilities options e.g. 100% copper instead of FTTC/P, IGT gas supply instead of Transco etc.
I know this doesn't help the OP, but since 2015/2016 Openreach do not charge extra for installing FTTP on a new build site versus copper provided there's at least 30 properties being built. I suspect the OP's site was started well before OR decided to offer this.
OP, first of all you need to find out what, if any, plans are for FTTC/P in your area
by looking on the Openreach Superfast site:
https://www.homeandwork.openreach.co.uk/when-can-i-g...
If there's no plans then get in touch with you local MP, make a big song & dance about it and then you might get somewhere. You may also want to club together with your neighbours/other residents and self fund a FTTC cabinet or even FTTP through Openreach.
If I was in your shoes and the developer was still building houses, I would stick a slow broadband poster in my window with a nice picture of a snail which every potential customer could see. That may just spur the developer into doing something.
Edited by deleted (Wed 19-Jul-17 08:57:45)