If you read the article you'll notice that it's all opinion. The main quote about research is "There is disappointingly little peer-reviewed research on the effects earphones have on our daily lives and interactions." Even the linked "studies" are all correlation and mixed in with COVID.

The flaw in the whole argument is that somehow people are having less "meaningful" conversations because they headphones on. I'm sorry but you're not going to have a meaningful conversation (or any at all) with the 100 people who are also actively running at the park whether or not they had headphones on. I still don't see it as a problem if 100% of the people running had headphones on; they are there to run! It's like saying there's a problem because 50 out of 100 people at the park having running shoes on. If you've pre-decided that running shoes are a problem then that's a big concern otherwise it's just nothing.

For me, if I didn't have headphones on I wouldn't be going for a walk/run at all. That one thing has drastically changed how I approach exercise in general and I would do less without them. That said, I do occasionally enjoy a nice walk/run without any headphones but as the exception rather than the rule.