From a supply/demand perspective, if all of your customers are still getting high on the 5 (or 20) year old supply, launching a new title in the same space isn't going to work. There are not an infinite # of gamers and the global dopamine budget is limited.
Launching a game like TF2 or Starcraft 2 in 2025 would be viewed as a business catastrophe by the metrics most AAA studios are currently operating under. Monthly ARPU for gamers years after purchasing the Orange Box was approximately $0.00. Giving gamers access to that strong of a drug would ruin the demand for other products.