You can. In fact, my brother did so a bunch of years ago. He found it to be a wonderful experience that made his life better.
He's also flown on a commercial airplane from NY to LA (as have I, as well as millions of others) and while it got him to Los Angeles, it didn't provide the levels of sensory input, personal interactions and experience that riding his bicycle did.
That's not to say everyone should ride bicycles across the US every time they need/want to make such a trip, but doing so at least once can be a more positive experience than sitting next to some strangers for five hours.
The satisfaction of doing so, or the experiences in interacting with people and the landscape during such a trip aren't quantifiable, but reducing the value of doing so (if I'm missing your point here, my apologies) to the time required to make such a trip is reductive in the extreme IMHO.
