Both.
8 years of Catholic School. Tested for the LSAT and found out the most Holy, but not so good at math, Catholic School mailed in the math part to the kids. I got a good, moral and religious education. It was worth it to go.
However, they COMPLETELY whiffed at the math bit. I taught myself about three years of stuff I missed and ended up scoring well on the SAT.
Add to that most of the kids going into public high school with me from the local junior high had already passed Algebra. We didn’t offer it, and my janitor father and stoned-out mother wouldn’t have thought to even ask? My Dad is extremely bright, but his upbringing was done on his own.
So I’m now in HS, in Algebra with sophomores, juniors, and seniors too stupid to pass it in 7th or 8th grade, whilst my peers were off to Geometry, and ended up taking Calculus and passing it before they graduated.
I went to another government school after that (USCGA) and then found out our particular government HS didn’t offer AP classes. Most of my engineering classmates passed a year’s worth of gut classes and basic math courses and were off to multivariable calc and diffy q.
I caught up by overloading at the government college.
Throughout my HS and college bit I ran into one amazing master teacher after another, especially in math, but definitely in English. Our English 2 Advanced teacher insisted we draw and support our own conclusions on everything. He took the opposite side of every argument and expected you to win. If you didn’t, he’d show you why you could have, then insist you take the other side and defend it. He taught me how to challenge every assumption, and as a result, he taught me how questioning the basic tenets of my faith has made me a stronger Christian.
So, in my experience, it’s almost never the institution that delivers the goods to the student. Each teacher is either effective or isn’t, and much of that depends on how each student learns most effectively.
Most accurate thing I can say about any of my teachers goes something like:
“For me, this teacher was able/unable to effectively impart the curriculum they intended to impart to me.”
I can’t even make a blanket statement that some teachers are ‘excellent’, because obviously some kids leave their classroom not getting it. All I can proclaim is that ‘for me and me alone’ this teacher was effective, etc.
Nothing pisses me off more than an auto-didactive person to look down their nose at some experiential learner and say, “The textbook had everything you needed. How come you failed?” It’s arrogant.