There's no reason to believe that people, teams and organisations can't learn lessons. This is why we foster a growth mindset. It takes effort and discipline but it can be done.
There are teams that want to improve the code but get tired of fighting management, but if you go in as senior IC and encourage them, showing it as a heroic fight for the good, the true and the beautiful, they will respond with relief and eagerness and many idea to improve things, and a willingness to find ways to marry the management requests with the proper long term quality way.
