Kamiizumi Nobutsuna from the 1500s...correct?
No doubt some it was passed down, however, many of the styles changed emphasis over the centuries. Therefore, in some cases you are not necessarily inheriting the "it's all practical" format.
Which is why one must be discerning in what one learns. The spirit of the ryu, however, tends to be rather well-preserved, and hence the principles of what one must learn to fight are still there.
Re: What you listed about Hsing -si. Parlor tricks pulled off in a controlled environment.
How controlled are we talking about here? My old sifu basically asked me to come at him any way I chose. Sometimes he'd just sit there and let me pound him in the body a couple of times while smirking at me, and other times he'd step a hair out of the way and whomp me, sending me literally ten to twenty feet back. I'd put money on someone who's gone beyond the forms of hsing-i anyday.
I'm a cynic at heart. My faith in the classical forms stems from direct experience. You may or may not believe me; all I can say is get thee to a school where the old techniques are living and breathing, and see for yourself.
Roberto Valenzuela
Owari Kan-ryu sojutsu (尾張貫流槍術)
Shinkage-ryu heiho (新陰流兵法)
"Be intelligent, but do not be artificially intelligent." --Kung Fu Proverb
"Culture Check: Korean Arts still determined to make indigenous martial history from 4,000 year old cave drawings. France counters by claiming Savaate developed from hunting woolly mammoths before Ice Age." --The Nth Degree