I've done Ensimag, which is a public school in the same sector, and you definitely could skip classes if you wanted to (though most of the ones who skipped classes did it out of sloppiness)
Those who had issues were those who needed to be told where and what exactly to look for. They often felt like they were paying for little to no teaching (which is true, in a sense, but I preferred to see it as an opportunity to grow by myself in an environment where I could have extra resources at my disposal if I needed to - the best one often being other students, sometimes from previous years).
And once again, all engineering schools considers their students adult enough to let them do their thing: there's no repercussion if you don't go to classes, it's not 42-specific
I graduated from an enginnering school, and you can absolutely skip all classes if you wanted to. Sure, the teachers don't encourage you to do it, but the freedom is definitely there.
BUT, since there will always be a percentage of students who don't succeed in a "traditional" way, a bunch of rich people will always attempt to lure them into a paid program (which is, I repeat, selective). So they learn quite a bit, and they can become high-earners in the future, since they're all hanging out with technically good people.
For example, one key part for me was that the school allowed me to practically don't go to classes as long as I could prove that my work wasn't affected. It's something that you won't find everyday. I'm 100% sure I'd have failed university otherwise because the lack of freedom would have bored me to death Conversely, friends of mine have dropped from Epitech in the first two years because they didn't get enough support, so it shows that the most interesting thing the school has to offer is its learning devices. They understood that one size doesn't fit all (which is against the French public school philosophy).
So yeah, the tuition is expensive (and frankly given how the school works you sometimes wonder whether they eat luxury cars for lunch), but there's simply no public alternative.
One other factor I've also wondered is if people paying for their scholarships weren't more invested in making it a success? I knew my fair share of people who weren't thriving as developers at Epitech as well, mind you, but most of them dropped before the end.