When I was a kid, I used to have this argument with my friends that anyone could learn anywhere, irrespective of who was teaching them and how they were being taught. I always said that to them because unlike me, my friends attended government schools at the time that were known to be filled with rascals, and that was me trying to let them know that they could learn if they wanted to.
Although some of it was true, it wasn't entirely true. During my primary school days, I had encountered the worse teacher that I've ever met in my life. This teacher at the time derived joy just by knowing that he was being feared by the students. It was something he wanted, and was super glad he got it.
I remember how I would always refuse to go to school whenever I was late for class, even if it was by a minute, and I would cry until my parents followed me to school, as that was the only way I knew I could avoid being punished. One time my dad had escorted me to school and tried talking to him about the way he punishes us, and I could have sworn I saw a huge smile on his face when my dad left, he was enjoying the fact that I was that scared of him... Me, a little kid.
Funny enough, one would think that all of that fear would make us study more and focus on what we were being taught in class, it didn't. Instead, we only studied because we didn't want to get punished, not because we understood anything that was being taught.
When he eventually left the school (he got sacked), everyone of us had celebrated, because we were no longer under that tyrant who was having a good time making our lives hell. Immediately, everything he had forced us to learn through fear and torture disappeared from our brains because that fear factor was no longer there.
Fast forward to some years later, I was getting ready to take my Waec exams and was going for lessons at the time. During this particular class, we had a teacher who always looked for various ways to try to make us lsugh and just have a good time while he taught us what we needed to know about the subject.
I always looked forward to his class whenever I went for lessons and I remember that whenever he asked us what topic we studied the last time, almost everyone was quick to answer because we all always remembered due to how fun his classes were.
So if you ask me, a student performing poorly could be either the teacher's fault or the student's fault. For the teacher, it just depends on who's teaching and how they teach, because different students learn in different ways and not everyone is used to the strict kinda method the first teacher in my story used.
While for the students, sometimes no matter what method of teaching you use as a teacher, even when you give your best, there are certain students that just would refuse to learn.. And that is why I say that it depends.