Firstly, yes PC is mostly digital only, but there is at least competition between PC gaming marketplaces, which helps to restrict anti-consumer practices like deleting content that gamers have paid for.

Secondly, some of the competitors in the PC gaming space allow for physical backups of installation media, which helps with game preservation. For example, if a game is bought on GOG, the installer is mostly/always one that can be backed up onto physical media.

Thirdly, while it's true most gamers have moved away from physical media, it still has value. For example, second hand games allow for more people to take part in gaming than could otherwise (legally) do so. Taking away physical games won't stop people on low incomes from wanting to game, and is likely to lead to a resurgence in game piracy. Not exactly the outcome game industry leaders are likely to welcome.