Blu Ray Vs Sky/ Streaming

My suspicions are that cable/satellite providers 'cheat' to cram more channels by reducing data rates.

That results in macroblocking and subpar picture/sound quality.

For streaming Netflix 4K HD is excellent over cable or optical lines. You need consistently good download speed - minimum is 30 Mbps. For viewing there is nothing that compares to UHD 4K Blu-ray with a proper player and a 4K UHD TV. As far as TV goes, I rate the LG OLED 65E6P and equivalent 2016 top LG OLED models as the best picture available today.

Satellite is always lower quality.

Thanks for the reply, could it also be that we may loose more through the transmission from Sky, and the fact the sky built box components won't be as good as say a £400 Blu Ray ? 
Both above reasons makes sense to me. I guess most of the viewers won't notice. Maybe it's just us audiophiles that pick up on this , but whenever a good film is released I will always wait for blu Ray instead of the sky version . 

Not sure why no one has touched on this, but the reason that blu-ray looks better than cable, sat, and online streaming is fairly simple - it has to do with compression. Blu-ray uses minimal compression to maximize video and audio quality, and can do this because a typical blu-ray disc (DL) can hold upwards of 50 gigs, which means they can deliver their content at a very high bit rate.

Cable, sat, and online streaming sites have to squeeze that content into a much smaller package (this is referred to as compression), and they do this for two reasons: 1. to be compatible with the relatively low internet speeds available across the country, and 2. (and this is the main reason) because it saves the ISP's a ton of money by not having to upgrade their infrastructure (servers, data lines, etc.) to be able to handle to increased bandwidth requirements. Hopefully, this clears up the confusion. :)

Cheers!

-David