Gachas are fun in the sense you start on a sinking ship on fire but eventually, around the 3rd year mark you stabilize and at the 5th year mark you kinda... beat the game? Sure, you don't have every unit but you probably piled enough experience, both of the game skills and out-of-game information like datamines, hidden stats and even how the devs behave to know what to prioritize. You also probably have most of the relevant units at this point too so 

Do I recommend people to stick around that long? Up to the individual, but I remember old Azur Lane players talking about how they mostly pile up resources now they were vets and I always wanted to see the game from the eyes of an old player.