Because of tank health, nothing is dying. Any dps is still susceptible to dying to a one clip, a hanzo arrow, a widow snipe etc even if they had 5 healers. Tanks have armor, too much health, shields etc, to protect along with all the heals.
In OWL if you really watch you see lucio’s dying often etc (me and my buddy kept laughing during Atlanta vs Philly at how many times Massa and the enemy lucio died)…things die, just not the tanks.
Rebuff tracer, and maybe more armor nerf (or get rid of armor in general). Brig is weak enough to work around with tracer now. Tracer can secure kill/harass the zen/lucio or if they rebuff Pulse bomb can also drop a tank like rein zarya etc very quickly.