There are plenty of new hobbies that nobody would call “superior forms of entertainment”. (Although it seems strange to gatekeep entertainment when its only utility is to the person enjoying it)

No one starts collecting stamps nowadays because, relatively, no-one receives stamps any more. An unusual stamp used to signify receiving an interesting letter -- perhaps a parcel, or a letter from a relative living abroad.

Without that experience, why would anyone start collecting them?

People still collect similar types of useless stuff (bottle caps, beer mats, guitar picks, fountain pens, license plates).