Yeah, no ****, Mercer shattered that glass jaw. Just like most boxers would against these cage fighters.:yep
I think in a street fight it depends on if the MMA guy knows off the bat the guy he's about to fight is a Boxer. If he does, he won't think twice about striking with him and just go for the takedown. If he doesn't, even an elite MMA guy is most likely going to strike with him first. In that case he'd probably get knocked out. Regardless of that, Boxers IMO who could hold their own in a street fight even against a top level MMA guy: Prime Tyson (could probably beat the crap out of most UFC guys) Foreman Liston Cotto (nothing crazy special but im pretty sure he wrestled in HS) Maidana Golovkin Pacquaio
You realize that top wrestlers are just as good at taking down guys that won't want to be taken down as top boxers are at punching guys who don't want to get punched, right? It takes top wrestlers their whole lives to get their takedowns and defenses optimized, so just because it's easy for you to say "they just have to learn to defend a takedown" doesn't mean they'll be able to do it no matter how long they try. Also, rather than just talking about this stuff, please feel free to try it out. Go to a gym and box for a while, then try kickboxing. You'll see that your stance and balance and movement changes and it's a hell of a lot different than pure boxing. Then throw in some takedowns and see how much you have to square up and how your defense changes. It's not nearly as simple as you'd like to think. But really, don't take my word, go and try it. You'll find that you enjoy both sports way more once you understand why and how they're different.
I don't know why people need to see some p4p best boxer lose an mma fight to know why just doing boxing won't cut it. Guys like Marcus Davis and Chris Lytle weren't top boxers, but they were good professionals with more boxing skill and experience than 99.999999% of boxers out there and when they fought they incorporated a whole lot more than just boxing into their game. They would have crushed any of their mma opponents in their whole careers in a straight boxing match but chose to use kicks and grappling as well. What does that tell you? It should tell you that being the superior boxer doesn't mean much when kicks and takedowns are in play and that would be true even if those guys were better boxers. That means PBF, Tyson, Golovkin etc would have to adjust their games as well. They're great athletes with amazing skill/balance/timing/coordination so I'm sure that they could do well in mma if that's what they'd been learning grappling since they were kids, but if being a ten times better boxer than your opponent in an mma fight doesn't do it, neither would being fifteen times better.