how come companies, museums, theatres, cinemas, don't consider fair use exceptions?

[bcnu]

You need to understand something: the right to copy is different from the right to ACCESS a copy.

For instance, if you want to watch a show, you can be required to submit to a physical search so the purveyors can be certain you're not going to make any recordings while you're there. If you don't like that rule, you can't get in. Simple enough. If you somehow violate that rule, you can be expelled from the premises if not also sued for damages.

If someone DOES let you in, and you DO make a recording, and don't get caught by the facility management, the copyright owners can still sue you for just about whatever you do with that unauthorized recording.

For example: By definition, there is no POSSIBLE way to record a live music performance without permission without being a copyright infringement. 17 USC § 1101. There is no "fair use" in that statute.