Originally Posted by c.kingsley
I don't think the quality is quite there yet but it is only a matter of time. There is no way that static disc formats can keep up with the evolution of streaming media long term. Better compression can be implemented at the application level and average bandwidth to the consumer will continue to increase. The content creators and distributors will naturally move in this direction because it allows them to protect and maximize their profits.
I have no doubt that streaming quality will surpass, current 1080p Blu-Ray in the next couple of years. There is some truth to the fact that the PQ of physical media is pretty much static for the life of that particular format, while streaming PQ can theoretically be upgraded more frequently, either by keeping the file size the same while improving the compression or by increasing the bit rate as the average consumer bandwidth increases.
However, with regards to improving compression, there is a catch. The biggest improvements in compression technologies come when they develop a new profile level or a whole new codec. While streaming providers could re-encode films every time a significant improvement is made in compression tech, the devices that consumers use to decode the content for playback must be compatible with whatever codec and profile level is used. For large jumps in quality, this might mean requiring the consumer to buy a new streaming device. For obvious reasons, the content providers don't want to push customers too much in this regard. Buying a new streaming device every 3 years is probably within reason. Forcing you to buy a new one every year is not.
This creates another issue. What if some consumers are willing to upgrade to a brand new streaming device every 3 years when the device first hits the market, but others take 6 months to a year longer. Does the content provider have to provide multiple versions of the same movie using different compression codecs in order to provide the higher quality for the early adopters while still supporting the consumers who take a bit longer to upgrade? Note that this would be in addition to the multiple quality levels they already have for each particular codec, which vary by bit rate in order to provide the optimal streaming experience for users with varying Internet bandwidths. Suddenly, instead of having to store 3 different quality levels of each title, they now have to store 6, or even 9. While storage is relatively cheap, there is still a point where it becomes a factor.
The key for physical media to hold an edge in quality over streaming over a period of 8-10 years is for it to be such a significant jump ahead of current streaming quality that it takes 8-10 years of advancements in compression and/or internet bandwidth to people's homes for streaming quality to catch up. Blu-Ray has been successful in doing this to date, but it's time is drawing to an end, at which point it should be replaced by a new, substantially better physical format and current Blu-Ray would be to the new format as DVD is to Blu-Ray now. I am skeptical that the next physical format will be able to hold an edge over streaming for a full 10 years if it is limited to 100 GB. However, the good news is that the current UHD phase schedule has 4K being replaced by 8K around 2020, which means it's supremacy won't have to last that long. It too would be replaced at that point, most likely by a different type of physical format since it doesn't seem that spinning optical discs have more than one more generation left in them. I'm guessing that an 8K physical media would be some sort of solid state drive/memory stick.