Well, I can't speak for you but it's pretty hard to see pixellation until you're about 1.5 m from my TV (60" 1080p).
My experience with TV upscaling is pretty bad, though. before I got HDMI cables for my player, the delay between the sound and the picture was noticeable (even by my mom, which is saying something). Then again, different TVs perform differently so YMMV.
What I was saying about sources is that most things today, when released in HD are 1080p. People with a 4k resolution TV would either not have the resolution they wanted, or an upscale, which BakaBT doesn't seem to advocate unless done perfectly; something I don't expect a TV to do. If TV's were advertised on PPI, then a 32" tv and a 34" TV would have different resolutions if PPI became a standard instead of resolution. Even then, movies would still be released in a certain resolution, which probably would be higher than 1080p, but still too high or too low for most people.