why don t people just travel their whole life?

Traveling is extremely expensive. You would have to have a movie star's paycheck to go on vacation for 6 months then work a little bit and start again and who hires people who leave for months then come back to work a little bit? What kind of flaky business would that be? If I go on leave for 1-2 weeks, I come back to new things. How do you catch up with changes after being absent for months?

Some people are itchy footed and need to move on every once in while or more often. I know lots of people like that. They go work on pipelines for a few months. It's punishing work, 12 hr days, plus a half day on Saturdays. You're too tired to spend the money and have minimal living costs. Then they go to Thailand and blow the money. You can do that for a few years but eventually body gives out. There are cushier travelling jobs too, like teaching. It's the same deal there. One day your health will give out. You won't have cultivated a safety net and you will be left in the dust by fresh, bright, young things. You always need to have a back up plan and a way out before you wear out.

Not everyone likes to travel. I find packing luggage, booking hotels & rental cars, dealing with airports and TSA security to be a hassle. So I really only travel when necessary.

Traveling requires SPENDING money rather than EARNING it. It's a luxury that most people can't afford. If you want to travel you can join the military and travel to beautiful Afghanistan. Here's a packing list for you:

1. Guns. Plenty of guns.
2. Oh and some ammunition too

Because you can't physically work your entire life and retirement costs money. Most people have to choose between traveling now and enjoying retirement. Plus, how easy do you think it is to get a job if you never keep one for more than a couple of months? Eventually, you'll be seen as an unreliable job hopper. No one will want you. Apart from that, in general, constant travel is a nightmare if you have children you're hoping to educate and provide got. Most people aren't cut out for homeschooling their kids, plus they need a stable income to provide a decent lifestyle for their child. Those are just some of the reasons. It's a lovely idea in theory, but so is drinking a six pack on a Sunday evening. At some point, you have to wake up to reality and it's going to hurt.

they don't do it because they can't count on getting a part time job to survive

Traveling costs money. Only the top 1% of society can afford to travel anywhere and anytime they want.

Most jobs are year-round and offer limited vacation time if at all.

It's hard to do. Getting the same job back isn't easy and if you can, it's likely to be entry level work.

The money spent during the travel months tends to be double what one would spend when at home.

only the rich can afford to to do this. If your poor an attempt this you will run into alottttt of problems.

most need to work full-time to pay for housing, food, utilities, clothing, transportation, etc.

Not everyone wants to travel, not to mention a lot of people have families and kids to look after. Also travelling is really expensive and most people can't afford it. I don't go travelling because I go on two holidays a year (one in this country with my boyfriend and his family, and one abroad with my mum. She's a doctor, so can afford it) and I'm jobless and only have so much money in the bank (some of which is from my parents and grandparents to put on a deposit for a flat in the future) and have attachments at home with my family and boyfriend. Also I'd be homesick after about a week.

It requires money. You need airplane tickets, bus fare, food money,etc. Unless you win the lottery, you have to work hard for your money before travelling.

Because 90% of jobs on this earth do not pay enough to allow that to happen.

Furthermore, most jobs are not going to be okay with their employees just going "Okay, going traveling for few months, see ya!"

if only money didn't rule over everythang

They don't do it because their job doesn't pay enough money over such a short period of time for them to be able to afford it.

Most people can't afford to.

Plus, most jobs don't give you that much vacation time.

Travelling isn't for everyone. I know some people who get home sick and they don't like having to constantly adjust to new places. Also most people can't afford to. That is why you should travel as much as you want in your 20s. You have less of an opportunity the older you get