Players that enjoy Apex Legends arenas should use more time playing, because it is most likely that Arena Game Mode will be removed from the game in Season 16.
Arenas were added as a permanent game option in Apex Legends Season 9 with the Legacy upgrade. Ranked Arenas were added to the game in Season 10 as a result of its popularity. And it was a huge victory for Respawn because many gamers expressed interest in this game mode.
The game mode has nothing in common with the original Battle Royale. Instead of 20 teams slugging it out over a long period of time, 6 players from two teams compete in a confined arena. Arenas have been a useful practice drill since they provided players with frequent combat, which is unattainable in basic BR.
Arenas, however, has become a dead-game mode owing to cheaters and exploiters. Except for a few players, hardly one plays Arenas anymore. Furthermore, Respawn and EA discontinued supporting Arenas because there haven't been many modifications to it since its release.
When Arenas was in its early stages, practically everyone admired it for its promise. However, it appears that the enthusiasm has worn off, and Arenas is now just another game mode gathering dust in the corner. So it makes no sense for it to be on the permanent playlist in the first place.
However, if Arenas is removed from the permanent game mode, other popular LTMs like Control, Gun Run, or the rumored TDM may take their place.
According to Thordan Smash, Arenas' demise is due to a reduction in Ranked Arena players and the creators' lack of interest in the game mode. However, there has been no official confirmation from Respawn.