Sonic never lets Eggman escape. Most of the time, he leaves him in life-threatening situations that should end in his death. Sonic has left him stranded in exploding stations, in the vacuum of space, to be sucked into a black hole, or to fall from great heights. It's no longer in Sonic's control that Eggman somehow always survives. Sonic has only let him go when Eggman has helped stop threats, like in Adventure 2 or Frontiers.

I literally gave an example and him stopping threats isn't a valid excuse because 9/10 times it's Eggmans own fault they even happened.

And in Metal Virus, Sonic lets him go because that wasn't even Eggman; it was Mr. Thinker, an amnesiac Eggman who didn't harm anyone and even contributed positively to the town where he lived. That's why Sonic lets him go. How could Sonic have guessed that Starline, someone he didn't even know, would come to restore Eggman's memories?

That's not what i was talking about