This is not a sustainable solution to population level health needs, even if maybe in your particular situation you do actually get enough vacation days and free time on weekends to be able to do this (I also doubt this).
For me the competing requirements are space for gym equipment and space for a workshop. I could have space for both if I lived further out, but then all other aspects of life would get worse. I'd have to drive constantly, to work, to social outings, to fun weekend stuff, it'd be a drag.
As you are pointing out though, we all have our tradeoffs we make. My only counterpoint would be that most cities are doing a terrible job of offering options to people who do want the more dense, "less car" communities.
A honest, objective comparison would be between going to a store in, say, LA or Amsterdam, and going to a lake or nice big park in LA or Amsterdam.
In Amsterdam, you can go to stores on foot without any issue. Not in LA.
In LA you need to drive for hours to go to any of the nice spots you listed. In Amsterdam you can walk to a nice park or a nice lake, and for the same amount of time you need to drive in LA to reach any decent spot, in Amsterdam you can actually reach at least two different countries, and by train you can reach spots like Paris.
For the mid-range activities we have to compare like with like. For some low-mid range activity (like a local park) indeed, walking in Amsterdam would be more convenient. Something more remote/infrequent (e.g. a specialized gym like a climbing gym or a large pool), I'd prefer to drive rather than take transit.
As for the surrounding area it doesn't really depend on the city itself, LA is surrounded by desert and mountains, Amsterdam is in one of the most historically agriculturally productive (and so, densely populated for centuries) and flat areas in Europe. If LA was built like Amsterdam, it'd still take forever to get anywhere interesting outside of the city.