Aside from doing the work to maintain and update your own engine, there is also the problem of onboarding new hires. If you use a standard you can go out and hire people already experienced with working on the engine. If you use your own, you have to teach a new hire to use it before they can be any help.
I read that this caused a lot of development woes on Halo Infinite for example.
I don’t know get why they would make it with UE5 when they have their own in-house engine.
Aside from doing the work to maintain and update your own engine, there is also the problem of onboarding new hires. If you use a standard you can go out and hire people already experienced with working on the engine. If you use your own, you have to teach a new hire to use it before they can be any help.
I read that this caused a lot of development woes on Halo Infinite for example.