One can see both sides of this rather lamentable situation:-
From a consumer's viewpoint the announcement probably adds more confusion than clarity.
Unless I'm missing something, only a very few new-build sites are likely to be equipped with fibre to the home and thus have genuine super-fast broadband.
The majority of urban homes in cities may be provided with Fibre-to-the-cabinet (FTTC) solutions, many of them competing directly with Virgin Media's superior co-axial cable from the cabinet. All those BT (retail and wholesale) customers lucky enough to obtain a FTTC solution will be relying on the existing D side aluminium and copper twisted pairs and thus only a very small proportion would seem likely to get anywhere near 40 mbps. (I believe Zen suggested that an average of 9 to 13 mbps was more likely.) Those still on DACS line splitters will obtain nothing, nor will those in sparser communities who are to be excluded from FTTC upgrades.
From BT's viewpoint there is perhaps some justification for painting a rosier picture, even if it is misty and murky in places, but I suggest a more realistic description of "slower copper cables" might demonstrate the urgent need for very significant investment.
Kind regards,
Walter