I can't imagine what they're gunning for, here. Ampere was on life-support with their Oracle deal and don't exactly corner any particular market. Cheap datacenter CPUs are AMD's priority position, efficient ARM datacenters are gravitating towards Nvidia and the HPC people are (like always) doing a variety of different things.

It makes sense to me why SoftBank in particular would want to own a competent ARM competitor in the datacenter, but I think they've got a lot of work ahead of them if they want Ampere to be competitive. For $6.5 billion dollars you might as well start from scratch with an architectural license and fresh designs.