Well see now this is the problem. Firstly, you are comparing Apple's legal service to pirated content and saying the pirated content has set a "broadcast" standard of 1080p. That's just silly. Secondly, you are insisting you can see the difference between 720p and 1080p on your TV at your viewing distance, but you are not making fair comparisons. All that 720p content is mighty highly compressed to save bandwidth. The 1080p content you are acquiring is probably compressed, but may be so to varying degrees. You can't in any fairness say you can see the diff between 720p and 1080p when you are comparing them from different sources using different transcoding software with different levels of lossy compression.
If I download a show vs watching the same show on my DVR, the DVR version looks a fair bit better. Both are 720p, just one has been downsized in a lossy manner. A high quality 1080p rip looks better on my TV than a low quality 720p rip, and my TV is 720p. You certainly can't compare a downloadable 720p version to the source 1080p version of a video fairly because the 720p version is a lossy transcode of the 1080p version. And whatever these 1080p versions are that you are getting… they may be lossy compared to the source, but the 720p is almost certainly more lossy. If you had a 720p version of your TV sitting next to yours playing the identical video, I'd wager you couldn't tell the difference.
Additionally, while Apple's 720p offerings will be lossy compared to the Blu-Ray equivalent, they are probably getting their copies made from the source material (which is much higher than even 1080p) and using very high end software. Their 720p videos will look a whole lot better than any 720p you could download that some schmuck made at home.