I don't pretend to have all of the answers, but here are a few thoughts on the subject, just for starters:

1-Classroom economics:

Many educational "enrichments" that were taken for granted--and were FREE, to boot!--in my generation have been either cut or the parents have to pony up extra money if their kids want to participate. Result: A less well-rounded education, and more time spent sitting quietly in a classroom.

When equal gender allocation of PE/sports assets was mandated by law, it may well have resulted in a net benefit for girls...but when dollars are short, it translates into a cutback for ALL PE/sports programs and a lot less opportunity for the boys to get out of the classroom, "get physical" and blow off some steam.

A higher student-to-teacher ratio translates into a greater need to maintain order in the classroom. This rewards the typical girls' behaviors and discourages the typical boys' behaviors.

2-"Typical" male and female strengths and weaknesses:

When it was recognized that girls/women tend to have less inborn/intuitive talent than boys/men for spacial-visual calculations--which applies directly to math skills--math and science programs were adjusted to help compensate. But even before the programs were adjusted, the girls weren't treated like "dummies" for being less-skilled in science and math; instead, they were directed toward their inherent strengths in terms of social, written and verbal skills. Being "not great" in math or science didn't automatically disqualify one from getting into a good "Liberal Arts" program. OTOH, a lack of verbal and written language skills is no longer being overlooked in those whose greater strengths lie in the sciences and mathematics, and this directly affects a great many boys. Furthermore, people who lack language skills are often put into "special education" programs--where kids who are dyslexic and/or rambunctious may be lumped in with those who have IQ deficits--rather than having the "mainstream" programs adjusted to help bring their skills up to par, as was done with the science/math-deficient girls. Why was this gender-based inequity allowed to happen? I'd imagine that it had a lot to do with a feeling that some sort of "compensation" was due to the newer generations of girls to make up for the past wrongs of channelling all/most women into the Liberal Arts. Boys weren't viewed as being due any "compensatory" programs (but maybe now that will change).

Girls-in-general are inherently more-content than boys to sit quietly and behave themselves. When PE/sports programs are cut, it doesn't impact the girls as much as the boys, because girls have less need to "blow off steam." It used to be that boys got most of the teacher's attention in class (and were therefore called-on more often, which translates to "positive reinforcement"); but nowadays, in a time when managing a classroom and keeping it quiet and orderly seems to receive the highest priority, the aggressive behavior that got positive attention in the past now may warrant a trip to the principal's office.

Are boys hating school and dropping out in record numbers? Yeah, it might be that way, or at least the trends seem to indicate that this might be what's happening. (It could also be true that male raw talent and experience is more-readily accepted by employers but that female candidates need to show educational credentials in order to land the high-level jobs...which, if true, would mean that all of this "rending of clothing and gnashing of teeth" in the press about there being fewer men in college is a non-issue.) What seems clear to me is that typically-girl-like behavior--the sort of behavior that gets a typical boy labeled as being a "wuss" by his peers and subjects him to merciless razzing and rejection--is the only sort of behavior that is being tolerated in today's classrooms.

3-One possible solution for public schools:

I'm not averse to gender-segregated education. I feel that it would do more good than it would do harm. Even in nursery/grade school, boys and girls tend to gravitate toward socializing exclusively with members of their own gender. Boys and girls--when they get to a certain age--tend to distract one another from their studies, and that is not a good thing--not for either gender. It would eliminate the pervasive problem of sexual harassment in the schools. It would help the girls to stay focused on their studies and worry less about their looks and their ability to keep boys "interested" (an "interest" that too-often leads to sexual activity before the students are mature-enough to handle it). Boys would be more-free to "act-out" and challenge one another, both in and out of class. And I would HOPE that, in this era of widely-accepted gender equity, that we wouldn't see a reversion to the girls' schools being given short shrift in terms of funding and other resources.

One could validly argue that segregating the sexes encourages, and even enforces, stereotypical gender-based behavior. But what we're doing now is pretending that girls and boys are all "the same," and we're only tolerating girl-like behavior in our schools. I believe that this is at the root of what seems to be happening with boys. And if a parent has, for example, an atypical or transsexual/gender-questioning child...well, there have always been problems with kids not "fitting in" in the public schools and/or the schools' teaching of subjects that the parents find objectionable, and that's why private schools and homeschooling are so popular.