Two common strawmen in favor of car dependency.
There are cheap electric bikes out there (at least much cheaper than a car). No need to be an athlete.
Disabled people are among those who suffer the most under car dependency. There should exist public transportation to go to parks for everyone, including disabled people.
Oh I am very aware and compassionate towards the dire state of mobility in the US. It’s just that you were dismissive of biking as if it had inherent insurmontable problems, whereas alternatives to cars are viable but have been suppressed politically.
Second point, it is not realistic to bike 3h one way to go to a far away park. But the question would be: does it make sense to go that far for a single day getaway? Wouldn’t it make more sense to have nice spaces in or around cities that people could go for an afternoon, but not expect to have true natural reserves commodified? People should have the right to accessible natural spaces, but the priority of reserves should be the nature, not the people. A massive presence of humans does damage.