there is another reason for that, and that is an Ubisoft problem (and other AAA studios), you cant make your teams do smaller projects because you cant split the teams, you cant use your 100 person studio and split it in 4 teams to do 4 small projects because you dont have 4 team leads or 4 leads of any of the departments. There are some big studios that evolved in the way of having multiple teams for multiple projects at the same time, that was common a long time ago with AA games, but the strategy is to always grow your team and company and at a certain point your studio isnt prepared to split up and tackle multiple smaller projects.
It sucks because a lot of franchises really dont need to scale up in scope sideways. Driver is a good example, you had it failing a lot trying to be GTA and having the character walk around and shoot, and the series only got good and strong again by leaving that aspect behind and focusing on how to grow with something truly meaningfull.
Still, Driver San Francisco was the last in the series so take that with a grain of salt.
Plus, you just know that if your promise is a game that can sell less to make a profit you will fail to get investment, they dont want just profit, they want a product that can sell a lot and bring the profit with it. If you start the design with the idea that it wont sell much (because it doesnt have to) you wont even sell the project to investors because they rarely care about the project, they care about numbers and sales