The percentage of people who were left handed magically rose from less than 1% to around 10% after we stopped persecuting people for being left handed. The same dynamic is at play here.

The thing about trans people is we're often an invisible minority. If you met me on the street or even were my coworker for years, you wouldn't know I'm trans. I'm a trans woman in my mid 30s. I simply don't bring it up with people who aren't really close to me. That's both for my own protection and because frankly, most of the time I just want people to see me as a woman, not as a trans woman. And just in case you're one of those people who thinks you can magically identify all the trans people around you, well confirmation bias is a thing. You only see the trans people you see. Some of us are out and proud gender-fucking pink haired gender studies majors, but most of us are just pretty regular boring people. We have jobs and lives like everyone else. I live with my husband in a 3 bed 2.5 bath house in a regular suburban neighborhood. You could be my neighbor or coworker and not know it.

In your age group, a lot live quiet sad lives never coming out because they don't want to disrupt what they do have. Or they transitioned and disappeared from everyone they once knew - that was incredibly common and the encouraged thing to do for trans people in your generation (if they were allowed to transition, the gatekeepers had to judge you able to pass and conventionally attractive to be allowed to transition). Back then you told no one, there's stories of trans women who transitioned, moved, and got married, and never told their husbands about their medical history beyond their infertility (although that was, presumably, unusual), other than very immediate family trans people fully disappeared. This was the way things were up until the 90s. And that's assuming they ever found the language to describe what was going on - a lot of trans people in your generation killed themselves without ever knowing why things were awful.

Of the people I knew before I came out as trans (in 2012, which was, as far as awareness and acceptance goes was a long time ago), there's at least a half dozen trans people. Obviously I've met a lot more since transitioning, and even not being out anymore I have had so many people come out to me as one of, if not the, first people they came out to. Also, non-binary folks are relatively new in the public consciousness (of course, they've always existed - certain forms of two spirit identities for example, or Public Universal Friend who found their own thing) and many of them would have simply been uncomfortable and gender non-conforming in generations past.

For a myriad of different reasons, "hetero and masculine" guys generally don't seem safe to come out to, especially ones in their 50s, so you only know about the trans people who have to be out to you (and not passing is one way of being forced out). If I met you IRL, I would never tell you I was trans, and you would never know. And I'm more willing to be out than trans people your age.

Research shows transgender individuals are younger on average than the U.S. population. We find that youth ages 13 to 17 are significantly more likely to identify as transgender (1.4%) than adults ages 65 or older (0.3%). https://williamsinstitute.law.ucla.edu/publications/trans-adults-united-states/#%3A%7E%3Atext=Over+1.6+million+adults+%28ages%2Ccompared+to+the+U.S.+population.

Have you considered that the ones you do know might not trust you or know you well enough to be open with you in particular? Or with members of your generation in particular?

Mid-30s here. Three close friends who are trans, and a sibling who is trans. I am cis hetero, so it's not about being surrounded by my peers. There's a reason anecdotal evidence isn't evidence and I suspect you and I are opposite ends of the scale showing why.