I have time because I don't have a wife or children. As great as that might be, it really does open up your schedule. I also have no interest in building a career, so I don't waste any time with it. I have the money, not because I make a lot, but because I live very cheaply on and off the trail. I don't own much of anything. I don't date. I have roommates, so only pay $100 a week for my living expenses.
It costs about a dollar per mile to hike a long trail, so if I think of buying something I don't need, I think of the miles I could hike instead. When I'm in a town, rather than spend $80 for a hotel, I'll just find a free inconspicuous place to sleep: parks, baseball field dugouts, behind abandoned buildings. I'd rather hike another 80 miles than have one night in a hotel.
I've used couchsurfing.org to get free places to stay also. And I've had people invite me into their homes without me asking. They like hearing the stories and being a part of your adventure. Fellow travelers have invited me to sleep on the floor of their hotel, and once someone offered to buy me and my friend a room at a hotel and a steak dinner (nothing creepy, he just gave us a hitch after I finished hiking the AT and handed us $150 to celebrate.) I used to turn down stuff like that, but I know how good it makes me feel to give someone something, so now I just take it and tell them how much I appreciate it.
Also, when you have the time and you live out of a backpack, you can hitch wherever you want to go, for free of course.
To me being rich is all about having more than you need. I've never been motivated to make a lot of money. I find it a lot easier and a lot more rewarding to just need less.
I'm going to see if I can continue to reduce my expenses while traveling. When I've gained more experience, I'll post about it at ABackpackersLife.com.