This question gets asked all the time in one form or another outtahouston. As you have, the question gets asked in terms of cost. But that is the wrong question to ask in my opinion. The question is not will it cost more to buy point to point tickets, the question is what impact on my travel will it have?
The answer is that regardless of how many people tell you that changing a RTW ticket enroute is possible and may not cost you too much, you are far less likely to react to opportunities that come up and far more likely to stick to a pre-planned itinerary. So it's FLEXIBILITY that you are giving up to save a few hundred bucks.
Consider this, suppose you arrive in a country and after being there a few days are offered an opportunity of some kind. It doesn't matter what. A job for the rest of the season, working on a sailboat that takes tourists out for day trips let's say. You happen to love sailing, it happens to be a great place to sail and you would quite like to spend the next 4 months doing this. But now your RTW ticket pops into your head. Uh-oh, if you spend the next 4 months in this place what happens with your bookings? What happens with its maximum 12 month validity? You may have to decide whether to pass on the opportunity or lose the total remaining value of the ticket.
Regardless of how many people tell you a RTW ticket is still flexible, it has very limited flexibility. That's what you have to make the decision on, not the cost difference.
