My parents were the primary caregivers for 3 of their parents. They never changed a single adult diaper. They also had kids, a mortgage with an interest rate that would make most people have a heart attack today, and student loan debt for two Masters degrees. My father changed careers when we were in elementary school, and spent 4 years unemployed/going to school. I think that's when they got really Mustachian. They would've been 40 years old. They both worked full-time the entire time for middle-class wages and benefits in a small town in the Midwest. They spent their minimal inheritances sending my sister and I to college (no student loans for us!).
And yet, somehow, my mother retired at age 55, pretty early for her peers and given the late start. My father could've done the same, but he was having too much fun with his second career. He's retired 8 years later, when the joy got sucked out of the job. They both exercise, my mother can paint and sew, they volunteer (politics and charities), are active in their HOA and church, take classes, travel... and they've always done these things. They probably had a decade when they let their hobbies slide, but once my sister and I were 10-12, I remember my folks had their own schedules.
Personal development and FIRE are attainable with children, but you need imagination, patience, and commitment.