President Rubio would be cruising to re-election right now
The media might not have given Rubio all the free attention it gave Trump, but it certainly wasn't unfair to him, since he was pretty consistently viewed as the strongest alternative to Trump until his "moment" in the debate. No way Rubio would've done better with an impartial media; his damage was self-inflicted.
Christie did a smart move on the debate because his ship was sinking and he started to sink Rubio's ship to get on Trump's good graces.