Youre point is well taken about Boxing being generally more popular globally than MMA.. but in the states thats not the case.
Even though these fighters are getting huge paychecks they are not selling out venues, and there is little to no public interest in Boxing throughout the year. Whhat has happened to this card would never happen to a UFC card.
I would say in the states they are about the same. Their ratings are about the same but I would still give the nod to boxing.
I think that your average casual suburban fan would rather watch a nobody UFC card compared to a nobody boxing card only because MMA fights tend to end alot faster.
I think when it comes to American fans that it depends on the demographic.
White suburbanites tend to favor MMA for whatever reason. I think thats due to no access to boxing and possibly because of wrestling being somewhat prevalent in high school sports.
But when you tend to go into urban areas I noticed that white people tend to be boxing fans more so than MMA fans.
Blacks and Latinos obviously are big boxing demographics.
Now having been in both suburban and "hood" neighborhoods, I think alot of it comes down to environment.
Suburban schools in general dont have alot of fights and when they do occur its alot of grabbing and grappling maybe some punches if your lucky, but not to much.
In inner city schools fights happen all the time and generally its with fists.
I have no idea if it correlates at all but it would seem that would tend to favor what style you grew up with. A black kid whos scrapped all his life might identify with a Mike Tyson over a Dan Henderson or Chuck Liddell the same way a HS state wrestler in Iowa might identify with Brock Lesnar more so than Adrien Broner.