Hmmm, true, but the "Sender" must still be compressing like hell, wouldn't they? Considering an uncompressed 1080p movie is ~50GB, and an 4k UHD Bluray (compressed) is ~75GB.... Netflix isn't going to press 75GB down your line in two hours (and a couple of 100.000 other lines at the same time)
Resolution and compression are two completely different things. You can compress an Ultra HD stream to 1kB/s (or lower, even) and it's still Ultra HD resolution - it'll just look awful. Here's a 320x213 image, compressed with JPEG at the 95 quality preset: Here's the same image at the same resolution, compressed at the 5 quality preset: Notice how both images are the same size (i.e. resolution), despite the fact one of 'em is 32kB and the other 2kB. That's compression: completely independent of the resolution of the image. A TV's upscaler is only ever active when viewing a feed which is below the TV's native resolution. It does nothing to improve the quality of heavily compressed streams, it just stops you from having to watch a tiny (but tack-sharp) window in the middle of your giant TV. Some TVs do have various image-futzing technologies designed to hide compression artefacts - my old Samsung Series 6 has a "digital noise reduction" setting - but they're basically just posh smoothing algorithms, and nine times out of ten you're better off turning 'em off: they usually make good quality streams look soft and make little difference to low quality streams. They're completely separate to the upscaler, though: as the name implies, all the upscaler does is scale the image up.
