"I can't tell much difference between putatively 4K content and clearly-1080P"
I presume the TV does upscaling? Not an expert, but theoretically a kick-ass algorithm should be able to gleam more resolution out of a temporally changing signal than the native resolution - thus actually providing more than 1080 pixels worth of resolution out of the 1080p stream.
When I bought a HD TV either the Blu-Ray player or my TV (can't recall anymore) upscaled my old DVD:s with surpising quality - I can only presume the same applies for the current generation (haven't had the chance to do detailed analysis).
I presume the TV does upscaling? Not an expert, but theoretically a kick-ass algorithm should be able to gleam more resolution out of a temporally changing signal than the native resolution - thus actually providing more than 1080 pixels worth of resolution out of the 1080p stream.
When I bought a HD TV either the Blu-Ray player or my TV (can't recall anymore) upscaled my old DVD:s with surpising quality - I can only presume the same applies for the current generation (haven't had the chance to do detailed analysis).
Experts please revise.