Nah Apple takes advantage of their walled off system. They know they have users and changing to an alternative is too difficult.
What their keyboards do offer is tighter integration. That’s not a wall, it’s more like growing enticing apples in the orchard within the garden.
Not much different than the situation with upgrades for my Volvo. The Volvo stuff is tightly integrated. OEM stuff sometimes involves compromises, like plugging things into the port and fiddling with bluetooth.