We didn't have these mixers at my high-school. Everyone was on his own.

I remember a friend of mine that had graduated about the same year saying that 20 years after graduation (i.e., age 38), only half his class had ever married.
Now that's really saying something. Religious schools are obviously big on pushing the idea of getting married. Yet even so, only half your classmates ended up getting married.
Goes to show: No matter how much the marriage idea gets instilled into the heads of teenage boys, if they attend school in a setting where they have no contact with the opposite sex, there's a high chance they won't grow into men a woman wants to marry.
Your high school was an anomaly. I have spoken to attendees of other all-male high schools and they all mentioned socials/dances in conjunction with the nearby all-female high schools.
Even in all-male high schools with dances/socials, individual dating success in high school was mostly dependent upon the strength of the individual male's K-8 era social network. If a male doesn't enter 9th grade at an all-male high school with a good social network of female friends/acquaintances, Grades 9-12 are going to be socially more difficult.
That person graduated high school in the 1980s. A 50% marriage rate for Gen X'ers who had ages 18-38 between the mid-1980s and mid-2000s would have been atrocious. That marriage rate would be a low marriage rate for Millennials turning 38 in the 2020s.
Gen X had higher marriage rates and earlier marriages than Gen Y/Millennials (the next generation after them).
I'm think that a lot of that 1980s graduating class was made up of academically gifted males who were socially stunted. STEM nerds might have been common too.
I'm saddened for you. White collar interviewing in the worst.
In the last 20-30 years, too many people have gotten college degrees and a lot of college degrees are worthless. There is now an oversupply of bachelor's degree + holding people pursuing white collar, office work.
Off the top of my head, there's only one guy I went to K-8 with who ended up attending an all male high school. I totally lost track of him (haven't seen him since 8th grade, nor had I ever even seen anything about him online...until a few minutes ago). After a quick Google search, I was able to find his wedding website. He's now married (to a wife whose looks are nothing special)
The wedding website mentioned how they met: They met at a bar shortly after he graduated college (in other words, he didn't have to rely on his existing K-8 social circle to get her)
Fellas who spent K-12 in male-only schools frequently begin having sex much sooner than the rest of us... It just ain't with women, and they're generally on the receiving end
Just like jail I suppose: Lots of sex, just not with the
opposite gender (and often times, they receive the sausage against their will)