With the SP content being light and Splatoon 2 only a month away.... is anyone worried that the player base will shrink severely?

It's literally the only thing keeping me from buying this game. At $80 (CAD) the game is just too much for me to invest in something that is reliant on a multiplayer user base to exist. I'm a competitive guy so would love ARMS... but I really do think most people will be switching over to Splatoon 2 as their go-to multiplayer game.