eval and include have some subtle differences but they are really underneath they are the same. Take this code and interpret it using the same parser and so much other stuff that is normally used. You will probably find they are more the same than they are different and to prove this if you look around you will find lists of differences not similarities.
Sure one might want a start tag but it's not a big difference. He wanted to know how it was possible to execute remote php script. On the PHP side both will work. Yes one starts in PHP scope and the other starts in output scope. It's not a major difference. I believe he was curious about the abstract concept. Not PHP specifics. I guess if you want them to work on the same URL prepend ?> to the eval string. Not a big deal.
"really a double infinite loop where the echo will never be reached"
The but and this end part are critical. The point was that it doesn't work. Yes, I was thinking it through as I wrote it, not pulling it from memory hence it the progression might be confusing however, you're making a fuss over nothing. I guess you people are as bored as I am.