I'd hardly say it's difficult to upgrade, they've been rolling out network upgrades for the last decade, starting with the 21cn network, then fttc and persumably ftth as an eventual goal.
They are rolling out FTTC, however slowly, and there was a lot of fighting, bureaucracy and political bargaining to do so; in addition to ruling out widespread FTTH rollout (only available to new-builds and selected rural areas).