If your academic talent is mediocre, like being in the 2nd or 3rd tier, isn't it better not to bother studying?

Back when getting a job was easy like before,
going to universities at the level of Pusan National/Kyungpook National/Konkuk-Dongguk-Hongik would have led to smooth employment...
But honestly, I feel like it's too ambiguous/uncertain these days.