I'm not that well-informed in the space but AFAIK Blu-ray remuxes (lossless rips) are often 50GB. Not only is that like 3-15x the size of a 4k stream for most providers, but plenty of folks don't even have the connection to download that real time. Also, lots of streaming boxes would choke trying to decode a data stream like that.

Sure different codecs (the process) and different encodes (the product) can be more or less efficient, and make different tradeoffs like prioritizing bit depth (prevent banding or blocky gradients like the sky) or bit rate (improve fine detail). Pretty sure tho overall throwing more data at the stream just gives better results across all discernible traits.

I do not recall ever seen that compression-related artifact stuff, on 4K BluRay, that I often see on streaming. Try a movie with alot of white water and you will see what I mean.

I think the physical discs, while lossy, are less lossy than streaming, the latter of which adapts based on circumstances to vary the lossy rate to ensure streaming does not pause?

tl:dr no one streams lossless rips because lossy rips are smaller and therefore cheaper.

Turns out lossy means you lose something.