I think you’re underrating the sheer amount of iteration that occurs. SaaS has requirements and then implementation- it’s a product that has a target it hits. Yes, churn happens, but the point is you’re working to a specific goal.

Games and any creative work isn’t like that. There’s constant iteration as new ideas come up or developers learn in play testing that certain parts of the game work better than others, and so they realign things continually and keep refining. I’m not a game dev btw, but blogs from devs show a continual cycle of refinement and feature creep.