That will NEVER happen.
Since G4 is over and G5 starts 100s of years of G4 so Rainbow Dash is dead.
The Sonic the Hedgehog company is still standing since we had Sonic Movie 2, Sonic Origns, Sonic Frontiers and Sonic Prime so Sonic will keep fighting Eggman throughout the years.

Actually, that could get interesting.

v You’re right. How about I use this one instead?  

Why did they use a picture of Eggman smelling his own farts?

Of course it could also be said that Chrysalis would win against any one of the Mane Six since she could take any of their friends forms.
 
Or Dr. Eggman could build (yet another) robot that looks like on of Sonic’s friends and use that against him and, blah, blah, blah, you get the idea.
 
Also, Chrysalis would suck Sonic dry of his love emotion? Can Sonic even experience emotions outside of “Radical!”?  
 
(I say that as a fan of the games, mind you.)

Rainbow Dash beat Dr. Eggman(Fuck Robotnik)  
Queen Chrysalis will suck Sonic dry of his love emotion.

>“Sonic probably would lose against Chrysalis though.”  
Then Princess Elise comes, gives him her love, and he beats her through the power of love.

^Yeah, but all Chrysalis would have to do is take the form of someone sonic knows.

@CannonFodder - They both win, since they’re heroes in children’s franchises and they NEVER lose. But seriously, it’s hard to picture either one actually losing.
 
But even better, make it Pinkie Pie vs. Dr. Eggman. Sounds more interesting to me.

No offense  
but Sonic is tough shit.

I’d actually like to see Sonic vs. Bowser and Mario vs. Eggman.

inb4 millions of PINGAS!

Rainbow would win against eggman.  
Sonic probably would lose against Chrysalis though.

inb4 millions of dislikes