I've traveled to 50 countries and lived in 7.
I don't think being well traveled is about distance or number of countries visited... For me, it's more about whether you've traveled independently and built some skills of adaptability and resilience to deal with new situations. That can happen with as little as one new foreign country.
For me, a well-traveled person is someone who can deal with all the stress, uncertainty, and chaos of travel. That can be as simple as ordering food in a language you don't speak, or deciphering an alphabet you're not familiar with to get on the right bus. Heck, it can happen in your own country, some times.
But once you've done something like that, the kind of travel skill you develop is pretty universal. Not to say no place in the world will ever throw you a curve ball, but once you accept not everything works like it does in your country and you learn to stay cool under pressure when nothing makes sense, you're well on your way to being able to thrive anywhere you go.