It's not the size of the TV, but the quality of the TV. I run a 65" OLED so it's top of the line, but I can clearly see color banding from Netflix on pretty much any TV and it looks terrible. Overall it's just a lower bitrate and compression artifacts on both audio and video make the experience suffer.
Actually even at 1080p, Netflix streams are visibly worse quality than blu-ray. Particularly in the compression of dark colors. I'll occasionally see color-banding, which you never see in Blu-ray.
However... unless you have a UHD projector, or VERY large TV (60"+) then you are unlikely to see the difference under normal viewing.
Where I feel streaming typically fails, is in the audio. They may 'say' it's a 5.1 surround sound mix, but if so, why does it sound _so_ flat compared to the same film on blu-ray ? All I can think is that the audio is compression is also 4x as compressed which to our ears is quite significant.