I'm honestly not sure how much the team hopes for the game to last however I was thinking of long term structures that could help keep players engaged for longer periods. I know most people think they hate the grind but I really have found games with a FUN grind to be some of my favorites to play.
I think adding some form of shop for pets whenever their skill tree is maxed out would help with this by being a permanent Pansun dump. Some items could include increase egg drop chance (another suggestion about eggs with different upgrades to the temtems), start with a free gear, start with a free technique. Just something to give players who enjoy the game something to always have going on after the game too.
(This could also allow lowering the cost to max out skill trees so players have more feeling of impact per match)