By passer rating and QBR Kyler still sits well outside the top 6-8 quarterbacks in the league and in that 9-16 muddle. That's why it's a challenge to consider replacing him. It's pretty stunning that Kyler hasn't meaningfully improved since his rookie season, and in some critical ways maybe has gotten worse.
There are some QBs who don't really "get their teams to the playoffs" -- there are 2-3 every year. I'd point to Pittsburgh and Green Bay this past season, Cleveland, Philly, and Pittsburgh the year before. My POV has consistently been that you do everything you can to make the playoffs consistently -- sooner or later you're likely to break through. I think that Kyler can be a guy that doesn't put you out of the running to make the playoffs. I want to see a couple more chances before I decide he really is Kirk Cousins But Runs.