Are you hard wiring to the internet or using Wi-fi? Also which Netflix package have you subscribed too?
A uncompressed 4K movie would need approximately 5-10 TB of storage. Which would be impossible to distribute. Its compressed using the H265 codec. So it can fit on a blu ray disc. I agree its loads better then a stream
Streams are compressed more. Maybe in the future when we all have Gbps connections, streaming will be superior to disc, but that won't be for a long time, as bandwidth is still a factor from the source. The compression on streams like Netflix with dark scenes really annoys me. It's showing up everywhere now.
I stand corrected thought I had remembered them not being for some reason still they are usually noticeably better than streams