This is ancient.
It was already settled way back in UFC#1.
The pure Jiu-Jitsu fighter beat the boxer without so much as a scratch.
Even ninjas beat boxers apparently:
Francois Botha was a pretty good boxer(he went 10 or 12 rounds with Tyson, and had him beat on points before being knocked out).
Well his record as a kickboxer was like 2-10. And his two victories were over guys with injuries.
So boxing is a great skill, as part of a larger skill set, but it doesn't do well in single-style vs. single-style matches.
It's too 1-dimensional.