Mike,
No one really asks us that.............we have bounced around the globe to complete our bucket list of all 7 continents, and since there is a bit of discussion if New Zealand should be its own continent (since it is technically on a separate continental shelf from Australia(), we have even completed out 8th before it is even its own continent ;)
No one asks the question, because those who know us know that we put a priority on visiting certain places (many in Europe and then many in other destinations, including some far-flung places in the US, like Hawaii). We made doing so a priority while we were still physically able to do so. A (thank God) short-lived very serious medical issue for one us (once it was cured) caused us to ratchet up our travels to 3 big trips a year (life is short or CAN be short).
Now that we did some grueling really long hauls (Asia about did us in), we now have a puppy and have stayed put for over a year (very unlike us), and friends know that we now have the "anchor dog." But, once our pup is of a certain age, we WILL travel again, as there are some additional places we would like to see.
But, on a very broad-based generalization, there is also the thought that traveling in our own country is easier (and will be easier as we age)..........no 21+ hour flights, not as many time zones to adjust to, and no international long distance plans to deal with........and should something happen, we are not worried about what third-world hospital we might be sent to temporarily before using upgrades medical evacuation on travel insurance go get back to home sweet home.
So, if your priorities are same as ours were, or even if they are different, just explain............people will understand, and when they run into you, they will ask where you have been and where you are going next. It look some adjustment for people to realize the puppy is now our key focus (along with some updates at our home)......but everyone knows now, and we exchange dog stories and then quickly ask about THEIR travels..........and we all know how people love to tell about their travel experiences............we get to be the kind listeners :)