I'm not sure how everyone else is doing during Covid-19, the lockdown and gyms being closed, but I'm personally down 12+lbs. True, some of that is muscle since I can't lift, but a lot of it was excess fat. The fact is, gyms are not always utilized correctly, and people can do better by getting proper exercise in the real world. The best use of a gym is inclement weather, week nights during the winter, or short duration high intensity weight training. Spending your weekends and even your summer week nights at the gym is a terrible way to get exercise. Walking (walking briskly or with a weighted pack if you feel walking is too easy, is still one of the absolute best forms of exercise in terms of risk vs benefits), hiking (even better than walking, introduces instability and elevation and usually involves that weighted pack), biking (mountain, road, gravel, even indoors - if you must), swimming (you don't need a pool to swim, open water is fun and free), paddling (whitewater, flatwater, rafting, rowing, SUP), running (though this is high risk, low reward, walking is far safer), trail running, yoga, body weight strength at home (there's some really hard routines, ever try an archer push up, how about a pistol squat, and of course all the variations of the pull-up), I could go on and on. Of course, you could also build a home gym, but not everyone has space for one.
The truth is, America has never had a very good work life balance and gyms were sort of the fast food of American fitness. We went there to maximize our limited time. I'm not sure if post lockdown we will have more time for recreation or less (I'm sure probably less, layoffs will mean more work for those still employed, not less) but Covid-19 showed that Americans aren't necessarily lazy, they just don't have the time for fitness. Maybe some of that is poor time management. Too much social media, too much TV. But I've got to also believe it's a crappy work life balance, combined with the current practice of fully scheduling childrens lives in programs.
So, while I don't think you can replace lifting heavy at a gym, there is absolutely no reason to have put 15lbs on during Covid-19 lockdown. And there is absolutely no reason to return to a gym for till at least October 2020. Enjoy the nice weather. Enjoy the sun, the outdoors. Enjoy the summer. Enjoy Fall foliage. Enjoy getting fit outside.