It's seen as a gift because employees have come to treat it as a perk. There's isn't a good negotiation reason for an employer to treat it as a default because they can use it as leverage to get less salary from you in return for remote.

As long as candidates see it as a possible alternative to additional compensation, it'll be treated as a perk that can be revoked. Execs would do the same thing with bathroom access or access to drinking water if it was practical.