Not earning is not the only missed financial opportunity: all the money that goes to travelling could be invested at a young age. With investments time is the most valuable resource. I quit at the age of 35 from the hard software engineering jobs just like many of my friends, because we burned out / wanted to come back to our home towns.

The difference between our quality of life (and especially fear of needing to go back to work) is huge.

Travelling is pretty easy though when you have time and money at this age, I don't feel that I missed out on some travel when I was younger.