A big part of schooling that I didn't realize until I was an adult is learning self discipline. The boring terrible class you hate and can't pay attention for is a feature, not a bug. You ought to learn how to get over yourself, be able to dig in on something uninteresting, and get what you need to get done. That is probably the single greatest skill schools teach people entering adult hood. Unfortunately it only takes for some students. Those students who always get As, who went on to med school and what not. How did they do it? Probably by getting over themselves as a step one. I wish I could slap my 16 year old self across the head.
Rest assured, if you force students to learn basic english and math, the vast majority of students will experience this as being forced to study things they don't care about.
The difference with what I'm suggesting is that they won't be forced to learn about 7 or 8 different things they don't care about at the same time.
The allocation of teachers' time will be better with a more constrained curriculum, and the classes where students choose to learn about a subject will be a more engaged.
Framing learning things you're uninterested in as "learning to get over yourself" is odd. This isn't an ego problem, and dictating personality traits to such an extent is a questionable goal.
A couple years of work experience in grueling or soul crushing dead end jobs before going to college can do wonders for this dynamic.