is broadband unlimited deliberately slow to promote superfast

[Genetic]

I have had broadband unlimited for a long time and have been repeatedly told that the av 5mps was dues to the final link being BT copper wire. I have now looked at part fibre superfast option which seems to  use the same BT copper wire to the house.. how can it be so much faster if the cables are the same?  is unlimited kept deliberately slow as over £26 per month for 5mps seems too high

[TimmyBGood]

@Genetic 

'Superfast' FTTC is a different technology to the much older 'Broadband Unlimited' ADSL, with a different distribution topology.  ADSL is copper all the way from the telephone exchange, while FTTC is fibre-optic as far as a local cabinet.

https://helpforum.sky.com/t5/Broadband-Talk/Changes-to-how-we-talk-about-Sky-Broadband/ 

ADSL ('copper') has a maximum speed of 24Mbs, while for FTTC ('part fibre') it's 80Mbs: both are reduced by the length of the copper line.