"Eh? What is this gobbledygook?", said the 70% of users with ADSL packages. "FTTC? BDUK? I know 20/20 is good vision, but 55/10?"
With all this techno-babble around broadband, no wonder a large proportion just go by price. It's something they understand, and they just run the router supplied with their first package assuming that the vendor set it up correctly.
For deeper penetration, broadband probably needs an A-E rating akin to white-goods. That way the 'better' A rating will be chosen by households who treat their internet access as a fridge, i.e. they buy it and it works. If we look at the transition of the personal computing market from technical savvy PC owners to closed box phablet owners, I suspect that is the vast majority of households.