Ofcom seem to be a bit hesitant to impose things the providers will not agree to, although they are nowhere near as bad as Ofgem.
Regulation is inconsistent as you have pointed out, even within Ofcom its inconsistent as an example they recently stopped the practice of not removing cost of phones from mobile phone tariffs that included a device, but it still took them many years to do that. They had the chance to do something when they were consulting on the in contract price increases, but they decided to do a light touch change which was to prevent increases based on a unknown future number such as future inflation but providers are still allowed to impose fix cost increases.
For as long as they allow in contract increases I think there is no chance they will forbid this kind of discrimination. Ofcom arguably may actually want consumers to be constantly switching ISPs as they can then consider that evidence of a competitive marketplace.
