The budgets of modern AAA games have reached absurd proportions: projects costing hundreds of millions of dollars are practically impossible to recoup through standard sales alone. Now Microsoft, which has to rebuild Xbox's position, has encountered yet another problem.
Former senior producer at The Coalition Derek Reese explained why maintaining the studio is so expensive. According to him, Microsoft does not want to utilize the team's custom version of Unreal Engine, preferring other technologies, including ForzaTech. As a result, hundreds of millions of dollars are spent not only on making games, but also on supporting an entire technological infrastructure.
A significant portion of these expenses is due to the fact that The Coalition is responsible for developing Microsoft’s custom branch of Unreal Engine and for one of the company's flagship projects.
I know this because I tried to convince leadership myself to support a plan where other studios would start using this engine. That would have helped distribute the costs of maintaining it.
The situation with Turn 10 and ForzaTech is exactly the same.