It's actually a helpful example to support the conclusion. Why would the author provide a "better" example that supports his/her idea less? LA to Chicago may not be a commonly travelled route nor one that would lend itself to train travel best, but the author's point still stands, which is in the US on average distances between major cities are much longer than any individual country in Europe, hence the immense cost required to build infrastructure for trains. We might have bit the bullet and done it with highways back in the day for whatever reason, today the reasoning for doing the same thing may not apply and the cost unjustified.