There is a reason why we see so many military early retirees.
You say that as if it's a fact.
My years of blogging experience, and a military retiree's PhD thesis (based on a survey), indicate that more than 80% of military retirees immediately embark on a bridge career. I'm not aware of any data which indicates that military retirees achieve retirement any sooner than the rest of their age group.
What about the other 20%? That still is very high compared to the general population, no?
Or do they take a short gap and then bridge career (wasn't clear since your qualifier was "immediately"), or are they disabled and thus you aren't counting them as early retired, or is there some other factor not mentioned?
I would love to find any surveys or DoD studies about financially-independent military retirees who never pursued a bridge career. (More than Spartana and other MMM forum members.) As near as I can tell from the past two decades, there are none. I'm afraid that I'm the lead researcher.
There
should be many more military veterans who reach FI on active duty or through a combination of active duty, Reserve/Guard service, and a high savings rate. It seems like a slam dunk: persistence, resilience, hard-core deprivation --> frugality, COLA'd pension, cheap healthcare. It's the conundrum which started the book project in 2004.
The other 20% of military retirees are dealing with significant disability, or going back to college (even in their 40s and 50s), or facing prolonged unemployment. I see those disability issues on PEBForum.com and many Facebook pages. I see the unemployment issues on Linkedin and several nonprofit sites.
The PhD candidate said that some of his data indicated that the more senior (in rank and/or age) the military retiree, the more likely they were to return to bridge careers right after military retirement. O-5s and O-6s were higher than 80% at returning to the workforce but there weren't enough survey responses for the confidence factor to include it in his thesis. Even retired admirals and generals who "don't have to work" tend to immediately get sucked up into corporate boards or paid billets at non-profits.
Gap years are more common today. (As late as the early 2000s it was perceived to be a resume gap, now it's "just spending a few months with family".) These tend to be families retiring at an overseas duty station and wanting to travel Europe & Asia before finding a job/home, or traveling the U.S. in an RV to find their mythical forever home. (They're usually advised to go where the job offer is, not waste their time seeking a clan homestead.) There's also a six-month wait before senior retirees (mostly officer) can be hired into federal civil service... if they're waiting on USAJobs then they're counted as "unemployed".
I spend a lot of time on military Facebook groups and forums where the vast majority of retiring servicemembers are stressed about succeeding in a civilian career. Their spouses are crazed with the drama of getting through the retirement process and the uncertainty of the bridge career search before the family can focus on housing & schools. The stress is evenly distributed among officers, enlisted, and ranks. It's all because military families have been living paycheck-to-paycheck for 20 years, or perhaps contributing just 10%-15% to their TSP accounts.
I know several military retirees (admirals, generals, and senior enlisted) who cheerfully admit that they'll never stop working. I know many more military retirees who are afraid that they'll never reach financial independence.
When I retired in 2002, there was exactly one other financially-independent military retiree on Early-Retirement.org who had retired immediately from active duty and never sought a bridge career. I was on several other forums where there were zero FI military retirees.
Today I know several FI military retirees. (One of them has been hiking the Appalachian Trail from end to end.) I know about two dozen military servicemembers who are either at or very close to FI and will retire from active duty in the next 1-5 years without worrying about a bridge career.
However the vast majority of my reader questions are about where to catch up on saving for retirement or how to find a bridge career-- not about what they'll do all day or how to use military Space A flights for slow travel.