I disagree with your thesis. When coronavirus was extant only in specific geographic hotspots, limiting travel makes sense. However, when it's present across the entire world at a low level - which seems quite likely to occur within the next month or two - then people traveling between regions is not going to increase the spread that much.
Right now it makes sense to tell people to stay in their homes. Once you lift that restriction, whether they're leaving their home to travel 20 miles or 1,000 miles is not that relevant.
Travel will be limited only as much as overall economic activity is limited, and there's no way we can maintain the current level of restrictions for the ~18 months it will take for a vaccine to become available.
If the countries are trying to do contact tracing and isolated quarantines where flare-ups are found, it absolutely matters.
This is what people are talking about at the moment when they mention easing lockdown restrictions.
Imagine a single government trying to get the word out to everyone who may have come into close contact with someone who flies from London to Berlin on a Friday, jumps on a train at the airport, parties for 48 hours, flies home on the Monday and feels ill/gets tested the following Wednesday. Then replace Berlin with "Liverpool" and see how that improves things.
Shoving a bunch of people in a small space for multiple hours to go to other crowded spaces with people from all over the world and then returning home with a bunch of other people in a crowded tube...
Tourism in my nearest city (Oxford, UK) had plummeted before any travel restrictions were in place. My guess is it won't come back very quickly after they are lifted.
Right now it makes sense to tell people to stay in their homes. Once you lift that restriction, whether they're leaving their home to travel 20 miles or 1,000 miles is not that relevant.
Travel will be limited only as much as overall economic activity is limited, and there's no way we can maintain the current level of restrictions for the ~18 months it will take for a vaccine to become available.