"Wish there were authentic spas here in the US like there are peppered all over the Occident and the Orient, but unfortunately, there just aren't. There are several reasons for that, as I understand. Pity."

There are a number of areas in the US with 'authentic' spas, including all the features, except medical supervision, you mention.
The northern Napa Valleyin CA, etc, is just one.

S