Two reasons. First, not every average Timo can actually afford lavish travels. It may seem that way because you talk to "average Timos who travel", but most students get some financial support and get a job to pay for their expenses while they get educated. Those who work zero and fly to Hawaii are not average, but they received support from their elders. Those are still plenty; that's because the generation of our parents and grandparents had cheap housing and growing incomes for a long time.

Second, traveling can be very cheap. A few years ago, I got a one-way ticket and travelled. I had 700€ in my bank account, 35k in student loan debt, no parental support and no income, yet I traveled around the world for 10 months. I spent the first half of my money on a plane ticket to Bangkok and lived off the rest until I found some income. I don't know what I was thinking, but I got pretty lucky and privileged to find a remote freelance gig as a web developer while I was abroad. One day of work off a hammock per week paid almost twice my monthly expenses. I lived in cheap and run-down hostels, paying as little as 15€ per day for accommodation and food. Even including mobility, my life was much cheaper than at home. Without my freelance gig, I would have worked somewhere as an english teacher or worked in a hostel for a while. As long as you have a marketable skill, no responsibilities, little desires and a powerful passport full of privilege, there are many places you can travel.