By that criteria Denver/Boulder, Seattle, Portland, etc. are way superior. Any kind of nature activity (hiking, backpacking, skiing, paragliding, cycling) is better and closer, except surfing perhaps.

With density that I until recently used to consider as an unquestionable positive becoming at least temporarily moot with covid (and frankly becoming permanently soured by the out of control protests - I realized I prefer my density Singapore style, with CCTVs and harsh sentencing), I can see why people would move out. I'd probably be out of Seattle, at the very least to the burbs nearby with the same access to everything and few of the downsides, if it was just me making the decision. Same applies to SF (I've lived in SF and Mountain View before, I'd say it's even more acute in SF, quality of life is just terrible even for someone who loves dense cities - might was well move to peninsula or east bay for better access to nature in essentially the same place).

I take it that he is referring to Rock Creek Park. And the C&O Canal Towpath doesn't cut through the middle of the city, but it is a fine place to go

LOL they're referring to Rock Creek Park, not the National Mall. RCP is probably the single best "urban" park system outside of Forest Park in Portland. I can walk out my door and be in nature in just a few minutes... you can walk or run all day and never leave the forest, yet still be in the middle of the city.

There's plenty of walkable greenspace in the DC area, but unless you live near a Metro stop or work remote, you will need a car and you will probably hate the traffic.

I think they're referring to Rock Creek Park, which runs down the middle of DC in the north and is run by the National Park Service.