Why would BT invest in fiber optics when it can continue to milk the copper cash cow?
It's not as simple as milking the copper cash cow. Consider what's behind this quote
“we need to be able to switch off the copper network. The economics don't make any sense if we keep the copper network running at the same time as we overbuild with a fibre network.”
Why don't the economics make sense? Because customers with a satisfactory copper connection, either POTS or FTTC won't want to pay FTTP prices. All fibre would be a much fatter cash cow. Make no mistake, if OpenReach can get rid of copper everyone pays more.