The main reason I would disagree with such a personally limiting view of the world is that the world is so complex and ever-shifting that this sacrifice (even i

The main reason I would disagree with such a personally limiting view of the world is that the world is so complex and ever-shifting that this sacrifice (even if you convinced a significant amount of people to join) ultimately cannot be measured in its impact. There are other things limiting travel is affecting, such as reducing the amount of income to the countries travelled to that otherwise really need it. But I can't really measure that to any significant degree either.