In my assessment, 2014 - 2015, we were dealing with the effects of a bad defense (combination of not filling it via the draft and free agency), then in 2016 - present, dealing with the effects of a horrendous offensive line, one which JR somewhat tried to draft for (and failed) but was never willing to sign top tier free agents. Gettlemen gets in and brings in a few new free agents, including a major investment in Solder, plus a high 2nd rounder in Hernandez, and the results simply haven't panned out. Solder may not be worth $15+mm per year, but no-one expected him to be this bad; you figure you at least expect an average starter on the line, not a complete fuck up and liability.
We are now dealing with the long term effects not being able to put together a coherent offensive line. I get the argument that if Rodgers, Mahomes, Wilson etc were QB, things wouldn't be that bad, but I think at best we'd be a 6-7 win team, so QB isn't the core of the issue in my estimation.