While there are certainly some tournament organizers who have that as their only or at least primary goal, there are several other worthwhile focus areas in tournaments such as showcasing a particular set of skills or a certain school of fencing.
A tournament's focus areas are reflected in the rules the organizer chooses to use. As an example, a rule set might reward "deep" targets more than "shallow" ones, reward whoever hits the other fencer first, give points for pulling off a certain set of techniques, etc.
This distinction between a duel fought in earnest and a tournament fight fought for some other purpose that tests a limited set of skills is found in several the sources and traditions that HEMA is based on:
The Bolognese tradition has competitive rules that disallow hand hits and give extra points for hitting the legs, which aren't exactly the most vital targets. (1)
The Franco-Belgian fencing guilds ran tournaments using a "king of the hill" format where the fencers were only allowed to hit with the flat, had limited target areas and the "king" was given advantages over the challenger. (3)
Fiore writes about having taught his students "both for fighting at the barrier and for mortal combat". (2)
So to conclude, tournaments can be geared towards certain aspects of historical fencing by tweaking the rules to reward the kind of behavior one wants to see. Simulating a realistic duel is certainly one valid approach, but it's not the only one worth exploring and certainly not necessarily the one the organizers of a given tournament have chosen.
(written by g2petter on reddit.com/r/wma)