That’s absolutely not true. Bluetooth has many “profiles” which define different capabilities. Here’s a list of them. These are all defined in the official bluetooth standards.
Maybe you were thinking of the “core specification” which defines the underlying protocol but doesn’t define the profiles? But that’s just the way they broke up the spec documents. The profiles are still official parts of bluetooth.
Apple’s proprietary extensions for audio are not part of any official specification though.
Unfortunately it’s very hard to buy a decent dumb TV these days.