It's up to the TV set, how it's configured and the experience of the viewer to notice differences not necessarily apparent at first glance.
Most porn releases can't compete with Hollywood mainstream feature film production levels in terms of picture quality. Gonzo porn material shot on solid camcorders, streamed and probably moderately compressed might look like a porn Blu-Ray Disc to some and not to others.
What's usually not comprehended is that data is a type of currency on the internet. To deliver more data in a given amount of time costs more. Not only the end consumer has to pay more for more. So it's reasonable economically for Apple and others to stream shitty material or offer it to be downloaded - it just doesn't have to do with good video.
1080p/30 Hollywood feature film material contained in what is called BD RIPs is far too common and kills any solid depiction of movement 1080p/24 offers. It just looks more like in cinemas for this alone already. Added unnecessary compression and frame rate changes in the transcoding - or ripping - process will lead to a noticeable degradation in quality if you know what to look for and the gear isn't bad.