I was just wondering what effect that one reverser inop could have had in the deceleration and had it made a significant difference in the actual stopping performance (regardless of what effect it had in the large left excursion from the runway C/L or in the possible fatal decission to attempt a G/A).
Considering the ALD calculations
here, with -6 % for two reversers (and implying at most -3 % for one) in case of MAX manual braking (with ca. 2000 feet to spare) and
here from another source of -9 % for MED autobrake with 1/2" water (giving ca. 340 feet to spare), I don't see how having one more reverser could have saved the day from the deceleration alone.
In another A320 overrun
accident (page 78, figure 2), which was due to complete brake failure, the average deceleration attained from aerodynamics and full reverse was just 0.9 m/s2 (about 0.09 G), with the aircraft leaving the pavement at about 55 kts after a ground run of 2000 m (ca. 6500 feet).
In other words, if you are getting insufficient deceleration from the braking due to whatever causes, aquaplaning, chemicals dissolved by rain, etc., reverse thrust is probably not going to make the critical difference between a high speed overrun or just a close call, at least in jets like A320.