I'm assuming that being a boxing ant has clear advantages if you meet another boxing nest, in that pretty much everyone lives; but disadvantage if you're facing a more ruthless opponent?
It's actually a disadvantage for both. Just because the defenders engage in ritualized combat doesn't mean they can't defend themselves, the ensuing battle will result in a tremedous bloodshed on both sides. Resources in the desert are scarse and even the vitorious colony might be not be able to recover it's losses before being attacked by another colony. Make no mistake though, if a colony realizes it's rival is much weaker its workers will be quick to attack in full force and plunder the enemy's honeypots - this ritualized boxing contest is mostly a measure to resolve disputes that aren't worth going all in and would probably result in a net loss even for the winning colony.
An even more extreme (and admittedly rather special) example of this are driver ants which when swarms meet will either immediately part ways or simply walk straight through each other - evolution has very quickly weeded out colonies that happened to attack each other (because usually none of those found themselves in a state capable of further survival after the dust had settled).
The reason certain ants (Lasius niger, Solenopsis invicta, etc.) happen to wipe out rival colonies so relentlessly is because for them it's usually fairly easy to recover their losses due to living in a far more resource-rich biome.
Edited by Serafine, April 8 2020 - 2:02 AM.