Only about 5 percent of active players use Minecraft on these older consoles, and the team has chosen to put its resources where the majority of people who play the game are. The PS4 will continue to receive updates, as will mobile and Windows 10 versions.
The Xbox One and Switch versions of the older game will not receive the Update Aquatic because users can upgrade to the newer version. Therefore only the newer version of the game on these two consoles will continue to be updated. But don't worry, this isn't a cash grab: Xbox One users can download the upgraded version of Minecraft from the Microsoft Store for free, and Switch users will receive the update as a free patch to the existing game.