This has been going on for a decade and there are multiple threads on the topic. Why not add to one of those?

The answer hasn't changed. Once upon a time, this practice was reserved for true convention hotels because exhibitors were using the adjoining hotel's mailroom to avoid drayage fees at the convention center. It then expanded to properties such as Baltimore's (50K sq. feet+ of event space) for roughly the same reason.

Properties then started outsourcing the mailroom, even though the guest does not see that back office function, because the administrative cost skyrocketed. That cost is either passed on through higher room rates or per package fees.

I am fine with a la carte pricing for non-essential services. There is no such thing as a "free" breakfast, gym or package service. The proper term is "included."