There is also the stereotypical "startup culture" ageism. Being a military reserves soldier sounded like an adventure when I was 17, but in my 20s it turned into a PITA and I didn't re-enlist. There's a lifestyle difference between "Bye Mom see ya after the deployment" vs "OMG I got a (real) job and house and car and bills and a dog WTF am I going to do now".
Aside from attitude, lumberjack sounds physically like fun when you're young and invincible, not so fun in your later years after you've actually cut down some trees. I've wielded a +1 chainsaw of storm recovery a couple times and its not so much fun after the first 12 hours on the job.