Why is SoloQ so painful?

Playing at Emissary (yes it's pisslow). Literally every other match I either get a leaver or a game that is 100% winnable but the entire team starts playing Team Deathmatch instead of actually playing the fucking game. I've had games where we lost with soul lead but the team refused to push walkers on multiple occasions.
Is there a way to force teammates to actually play together instead of dying alone? Pings/Voice lines and actually using mic doesn't always work. Focus lens/slowing hex are cool for stompers but I cannot motivate my team to play together.