They have similar beliefs but significant differences.
The RCC started out with nearly hundreds of people. And your attitude will certainly inspire more americans to disavow the self-righteous, supercilious attitude of the RCC.
You are incorrect. There are 23 additional rites in union with Rome. Some allow clergy to marry prior to ordination. None allow it after ordination.
Orthodox churches have beliefs very similar to all 24 Cathilic rites in union with the Chair of Peter. Seven sacraments, regconition of each others ordination, belief in the true presence of Christ in the Eucharist, Apostalic Succession to name a few of the core beliefs that they share.
Certainly there are some significant differences. Yet, the talks of reunification contiunue, and probably will for another generation or so.
There certainly are a few "american catholic" groups. There congrigations have "swelled" to nearly hundreds of people.