If we boil this article down to it’s most basic point, it actually has nothing to do with virtualization. The true issue here is actually centralized infra/application management. The article references two ESXi CVE’s that deal with compromised management interfaces. Imagine a scenario where we avoid virtualization by running Kubernetes on bare metal nodes, and each Pod gets exclusive assignment to a Node. If a threat actor has access to the Kubernetes management interface, and can exploit a vulnerability to access that management interface, it can immediately compromise everything within that Kubernetes cluster. We don’t even need to have a container management platform. Imagine a collection of bare-metal nodes managed by Ansible via Ansible Automation Platform (AAP). If a threat actor has access to AAP and exploit it, it then can compromise everything managed by that AAP instance. This author fundamentally misattributes the issue to virtualization. The issue is centralized management and there are significant benefits to using higher-order centralized management solutions.
In a centralized management scenario, the central controlling service needs the ability to control everything registered with it. So, if the central controlling service is compromised, it is very likely that everything it controlled is also compromised. There are ways to mitigate this at the application level, like role-based and group-based access controls. But, if the service itself is compromised rather than an individual’s credentials, then the application protections can likely all be bypassed. You can mitigate this a bit by giving each tenant their own deployment of the controlling service, with network isolation between tenants. But, even that is still not fool-proof.
Fundamentally, security is not solved by one golden thing. You need layers of protection. If one layer is compromised, others are hopefully still safe.