I don't think it'll be as bad as all that in the long run. The number of people hopping worlds while price shopping is likely a sliver of the over all population and like Brightamethyst said above, usually on big ticket items. I try to keep my own Market Board shopping to my local server because of time, but having the option to look around has been a godsend for my wallet. As an example, last night I needed to do my lvl 50 Carpenter quest which was making a Crab Bow with 1 Savage Aim III melded to it. On my world, the best price I could pay was over 100,000 for 52 of them in a stack. I don't have any interest in buying and flipping so I hopped over to another server just to see if I could get a better deal. First world I went to had a listing for 1 Savage Aim III for 3,000 which was reasonable for my needs.

The people who are going to be hunting for deals on every little things are likely the people who are looking to maximize their own profit. Most folks however are likely just fine shopping local. Never underestimate local convenience, as the large majority of people aren't going to obsessively shop around various worlds for everything.