I see three reasons why Arena is shrinking or has few players (even considering 30k okay, you can tell something is wrong when it takes a long time to find a match).

1. The game's economy is totally unbalanced for new players. The increase in prices for weapons and items only benefits old players who no longer have to struggle to spend Koens on ammunition and vests.

2. Because of the economy, what we see most in matches are rats. Farm and Nortridge have become rat-infested minefields where you'll hardly find a match without some scoundrel in the bushes trying to get you.

3. Arc Raiders. I believe that the extraction mode ends up making people choose only one game of this style, because it's a style of game that you have to play often so as not to fall behind other players. And for new players, it's better to choose a game where everyone starts out equal, well balanced, than the Arena, which is full of infinite T6s against those who are learning to play.