That most Americans do not have occasion to speak a language other than English day to day is exactly the reason most of them will not learn another language.
The "badly" problem is actually a really huge one.
The "badly" problem is actually a really huge one.
Why teach Latin, Greek, or Esperanto badly? How does that help?
And if you can solve the "badly" problem, why not teach something that can be used day-to-day?