All gacha games have huge power creep. If they don't, experienced players and whales have very little incentive to buy new units and keep the game developers solvent. If you're willing to play a lot you can mitigate it, though. For example, this game has been fairly generous with its jewels. I have a full water team built already, with a high tier SSR and most of the weapon grid filled with water weapons, and I will have 6k gems for this next event. If I want I could save even more for later events and get higher tier SSR/Eidolons.