drop bear
Sr. Grandmaster
Boxing wasn't designed. It's a game that people trained to get really good at. Because it was accessible and popular and competetive you got a greater variety of competitors and a faster trial and error weeding process for what worked within the confines of the game.
Now just because I call it a game doesn't mean I don't respect it, I very much do. But it's a different animal to a martial art. There are a lot of plusses to boxing, in fact I think boxing should be considered basic training for all striking arts because it's the best training tool for using the hands. But the limits it has mean that martial arts represent an increase in sophistication and complexity.
The problem you see of TMAists getting beat up by boxers is a combination of those practitioners having forgotten the basics of combat on which boxing is based, and of the limitations of the arena in which the tmaists are fighting and most importantly the unevolved training that they are using.
The last is the most important point because through training exercises like boxing we put ourselves through that weeding process, but not for our techniques; we were out our misconceptions about combat and so relearn those basics.
Your misconception there is you think street fighting is not a game. I mean yes anything could happen. And you could get any fighter up there on that roof top.
But honestly you probably won't. What you get is still a pretty insular environment with your martial art adapting to handle a relatively small gene pool of fighters.
Which is essentially how these boxing tents can go from town to town and not get killed by every hard man that comes along. These street fighters are still working within their own confines. In this case are limited by their training and their competition.