I'd say it's more on how the developers setup their system to utilize (or not utilize) those dynamic capabilities.
The game devs not taking advantage of that properly should be on them. Put the blame where it belongs.Don't let the devs off the hook just because you want to at least partially blame the MS cloud. Microsoft's systems CAN handle dynamic loads when setup properly, we see it all the time.
There is a nearly zero percent chance that the game developers are also cloud experts. Having the same parent company means almost nothing, especially when you get to the size of places like Microsoft. The internal bureaucracy can actually make getting things accomplished properly worse. External contracts are usually pretty clear on what's provided for the payment. Internal processes are often much more blurry, if not completely muddy.