I don't think so. Plusnet is BT's answer to Talktalk, and there's a *large* amount of business in that space - i.e. cheap as possible.
It is a bit perverse though that Plusnet's customer service is reputedly better than BT's.
My understanding is, BT branded retail customers will be eventually be moved to the EE brand as that is considered a better brand than BT nowadays and they can combine mobile and broadband products.