If you look at my profile, you will assume I am one of those guys you are wondering about in your second question. I am by no means wealthy, but I have been around. A lot of it really is technique--how you plan your trips makes a big difference.
First of all, my wife and I buy just about everything in our daily lives on credit cards that provide FF miles. We use very little cash. However, we stay in budget and pay off everything every month so that we don't accrue debt. We do, however, accrue a lot of FF miles.
Quite a few years ago we were planning our annual (off season and cheaper) vacation, and we decided to do it on Cozumel. We had been there once before and loved it. I am not a beach kind of guy, so I got certified in preparation for the trip. Diving there got me hooked, so from then on almost all of our annual vacations were planned to locations that are great for diving. My wife is not a diver, but she is an avid snorkeler and loves that kind of location, and I am mindful not to just spend the entire time diving by myself. Two tanks a day for most days is usually considered a good balance.
We are also very mindful of ways to make the most of our travel expenses. Flying is the big financial deal, so we start with figuring out what we can get for FF miles. We then make the most of a (usually) 2 week vacation. For example, we went for a week to Fiji and a week to Australia. It was an extremely economical trip because everything is so much less expensive in those countries. In another two week trip we did the ABC's in order: Aruba, Bonaire, and Curacao. On another trip, we spent a week on Cayman Brac (with an excursion to Little Cayman) and a week on Grand Cayman. Trust me, those trips were marvelous dive excursions that probably cost us a lot less than the typical vacations a lot of people take every year.
We have relatives in Florida, so I have mixed in dives when we visit them. With FF miles, it doesn't cost us much more than staying at home.
Some of my biggest trips, however, I have to admit were expensive, hit our budget hard, and took a lot of discussion. They had to be "trip of a lifetime" sorts of thing. (I've had several trips of a lifetime, so I am not sure of that definition.)
As a contract instructor associated with an LDS, I am sometimes asked to lead shop trips. That's a very nice and economical way to get to some of these locations.
Now that my wife and I are primarily retired, we have much more freedom. For example, my wife had to be away for a week earlier this spring, with only a week or so notice. It was the depths of the economic downturn, and prices were plunging. I got online and found an incredibly cheap last minute package to Cozumel.
Hope this is helpful.