Ever compare a Blu-ray to the same content over streaming? It's not even close. Unlike vinyl records, Blu-ray is vastly superior in quality to alternatives.
In case you're asking "why", it's because your "4K" stream is compressed to hell and back. Your home internet connection doesn't even have the bandwidth to stream the quality of a BR.
A UHD Bluray tops out at about 150Mbps, most home internet is capable of that. It would just cost too much for the streaming services to support it.
But also the reality is that most people have their devices connected through a shitty wi-fi connection and may be effectively limited to 50 or even less mbps, specially if you consider the unpredictability that comes with it.
True. Plus the big streaming services' business model now is low quality content produced in house or with cheap royalties, that people put on in the background. They might have a prestige show or two, but that's just a hook to get you to subscribe, they'd much prefer you watch the cheap stuff.
> Your home internet connection doesn't even have the bandwidth to stream the quality of a BR.
This has not been true for most people for a while now. Even the high end of 4K blue rays tops out around 100 Mbps, which is achievable on pretty much any broadband connection.
Netflix isn't serving 100Mbps though.
Are any streaming services actually serving that bitrate?