No one steps down they’re not a charity. Most coaches would analyze the game say they know this is not good enough, we need to improve, I take full responsibility, only way up is hard work etc.. until they get the sack.
But totally agree, his next job will likely be a second rate club not necessarily as low as Cagliari but can totally see him take over a top 4-6 team in Italy, France, Spain etc.. after a break and doing a decent job. Unai Emery is still getting good jobs and is remembered for more than just his worst time at Arsenal.
Ofc Emery never handled himself as poorly as Allegri has done recently with the statements and that makes matters worse but nevertheless he can still do okay elsewhere