Quality is another issue with downloadable media – though more so with video than audio. But acceptance of quality issues in audio has paved the way to a worse situation with video.
A few years ago, 128 kbps was the standard bitrate for stereo MP3 files. In a critical listening environment, 128 kbps is clearly overcompressed for most kinds of music. At one point, when hard drives were small and dialup modems were common, size was more important than quality to many. And most MP3 players (computers, iPods, etc.) do not qualify as a critical listening environment, so most people could not hear the degradation in quality.
(I have a theory that low-bitrate audio compression and poor quality portable audio devices has had a wide-ranging impact on modern music. But that is a topic for another day.)
As broadband connections became more common, and hard drive capacities expanded dramatically, the need for low bitrate audio files diminished. It is now practical to offer high bitrate or even lossless audio downloads.
Video requires a great deal more bandwidth than audio – by a factor of nearly 100:1 for standard def video and over 500:1 for high def video. Most video download platforms compress video approximately to the size of uncompressed audio. Amazon compresses its video 8 times as much as it does its audio, for example.
As a result, video download quality is, as a rule, worse than that of downloadable audio quality.
Unfortunately, while bandwidth has caught up with audio, there has been a bit of a fishbowl effect with video. As typical Internet connections have increased in bandwidth, digital media bitrates have increased to match, but typical broadband connections cannot support high quality SD video (without extreme download times), so there is no competitive advantage to be had in higher quality. Instead, media platforms have opted to differentiate themselves by offering higher resolution downloads.
DSL bitrates may (and probably will) go up, but based on the idea that bigger is better, digital media platforms have been offering HD resolution downloads rather than making the quality fit the available bandwidth.
The HD files commonly offered now are 720p resolution, but next up will be 1080p, and then 2k and 4k (and so on). Each step being taken will happen before the available bandwidth increases enough to accommodate the extra resolution. As a result, each increase in resolution will end up looking worse than the previous generation.
This is an unfortunate trend, and until gigabit speed broadband in the home is common, I do not see a reason for it to change. Certainly, there is no way to compete with the quality of Blu-Ray. But if quality were the only concern, Blu-Ray would be a wild success.