Fttp comes in two flavours
Point to point - as used by b4rn
Gpon as used by openreach
Gpon means a manifold per every 8 homes and fibre splitter per every 4 manifold
Fttp never goes to the cabinet it links to a bigger fibre splitter called aggregation node, usually near to cabinet and that will be already there.
You could install ducting and tubing and new pavement chambers to bt spec following a plan they create and then hand over for them to do the fibre blowing. This reduces costs to openreach and may make it commercially viable.