Re: When HDR becomes prevalent ...
Sky have the unfortunate but inevitable problem that they have restricted total bandwidth and increasing the available effective bandwith is a case of improved compression techniques or sticking yet another satellite up in orbit and having the receivers handle this. AIUI there is still (or was some) available capability on the receivers themselves which is very sensible and forward thinking of them but this still requires one or more satellites to be deployed to use it.
I have a lot of sympathy for the poor bastards at Sky (and VM and other similar digital providers) who have to manage the total bandwidth available and counter this against the guaranteed rates that some channels contractually require along with the negotiations for enhanced bandwidth bursts for premium events which force other channels into lower bandwidths during these events (try watching the less premium channels when a big sporting even is shown, for example). Some channels have minimum bandwidths with capacity up to a certain amount, some a fixed rate regardless, some with a desired rate but with contractually agreed drops to lower if necessary... basically every which way they can be agreed upon.
When the shift to adding HD channels came in this must have thrown even more complications into this mess with "standard" definition channels all being reduced in quality to allow the bandwidth for the "high" definition channels. The upshot of this was great for marketing drones because it accentuated the improvement given by HD channels... by reducing the quality of SD channels.
It's no wonder than your average digital channel has somewhat less quality than the previous analogue equivalent.