The example you gave, sounds like you possibly expect positivity in the response. But, the human condition often is not positive. People are trying to cope; some are doing better than others. In my first example, talking about people in general, it allows the conversation to shift to the general situation, and talking about people in general, rather than expecting the person to actually divulge information about himself to me, a complete stranger! (but, leaves open that possibility, say, if he lives with family, he is free to volunteer that if he so chooses.) In my second example, talking about my mom, allows the conversation to shift to ME, rather than making him feel that he has to talk about himself. However, he is free to do so if he wants, so, he could volunteer that he is having trouble getting his grandparents to voluntarily quarantine.
Another idea is to try a different topic! The pandemic is affecting people in many different ways, and, there are lots of differences of opinion as to what is the correct way the government should be handling it. So, when he says, "I'm good, how are you?" You could say, "I'm good, but because we are working from home, my dog is getting totally spoiled, and it's going to break his heart when we go back to work." Dogs!!! Everyone loves dogs! Always a great conversation! "You have a dog!? What kind is it? How old is he?"
See where this is going? Don't expect complete strangers to open up to you! Dogs, sports, weather. . . Find something to discuss that isn't personal!
Also realize you have no idea what someone is coping with. So, be prepared for some pretty heavy responses. My dog was diagnosed with cancer right when the pandemic started. I took him to the Emergency Room, an oncologist, and a radiation treatment vet, NONE of whom I ever got to meet face to face. I had to wait outside! It was stressful! If I were to tell you that story, are you prepared to deal with it? That's why it's better to try to keep it light!
Hopefully something I've said will help you as you re-evaluate how to approach strangers. Don't give up! It takes a lot of practice! If you are not at work, and just out and about, you could also find that wearing a particular t-shirt or baseball cap helps pave the way. A particular band or sports team, for example. Good luck!